Just a Wee Dot Like Doris - Hobby Downloads

" Just a Wee Dot Like Doris "

by “ L.B.S.C.“’

T HE above paraphrase of a famous Scottish do ; and thereby hangs a good laugh. A
comedian’s well-known song, will introduce
the little sister to “ Doris,” the L.M.S. 3-1/2in. follower of these notes says that he has a large
gauge class 5 engine, about which I promised, spam can, which once contained a goodly portion
by kind permission of our friend the K.B.P. to of that well-known wartime delicacy [?] and being
give a few details. Having had requests from a bit of a wag, suggests building a gauge “ I ”
plenty of beginners and inexperienced workers edition of the class of engine known on the
who are not only sadly lacking in equipment, Southern Region as “ spam cans,” utilising the
but also space for an outdoor line, to describe a metal of the actual spam can for the boiler
simple type of engine which can be easily and casing ; so the locomotive would be a spam can
cheaply built, and will run on an indoor line,
I have tried to kill all the birds with one shot. in fact as well as name ! ! Incidentally, joking
As far as general outline goes, “ Dot ” is a
faithful copy of her big sisters, bearing the propor- apart, it would be a jolly good wheeze, for this
tions and general appearance of the L.M.S. reason ; the boiler casing of the full-sized
“ spam can,” reproduced on the little one, could
class 5’s ; but her “works ” are simplified be made to serve as the outer case of the water-
tube boiler. It could be lined with asbestos
absolutely to rockbottom, and to the minimum millboard, to keep in the heat, and still leave
necessary for efficiency. A “ baby ” lathe. a plenty of room for a fair-sized inner barrel.
few hand tools,. and a one-pint blowlamp or If fitted with the same cylinders and motion that
small gas blowpipe, are all that will be needed, I am specifying for “ Dot,” the “ spam-can-ette ”
as long as the operator has the average amount would be a most efficient engine.
of what is known as “common savvy.” The
cost of the few castings and bits o f material “ Dot’s ” boiler is fired by a spirit lamp,
needed, should be within the capacity of anybody’s supplied with “ liquid poison-gas ” from a sump,
which is automatically kept filled to correct
finances ; and if the builder has any young level from a tank in the tender. The fittings
are cut to the bare minimum; no water-gauge
hopefuls who are mechanically minded, t h e little is needed, as the spirit flames cannot hurt the
engine will bring joy to their hearts, for it will boiler even if run dry. The boiler is fed from
not only pull about twenty coaches, but will a hand pump in the tender, a few strokes of
give them a ride. That is, of course, provided which everv five minutes or so. are sufficient to
that the kiddies can be persuaded to sit still on maintain a-working level. The tender itself is
just a half-size copy of the 3-1/2in. gauge tender,
a small flat car-the hardest job of all ! but need not be sprung, and is of simpler con-
struction. Now I’ll just briefly run through the
Specification in Brief
sequence of operations ; there- isn’t any need to
“ Dot’s ” frames are nearly all straight lines ;
waste time and space going into details, because
one evening’s work, easily. No hornbacks are the actual machining and fitting work is similar
needed, the axleboxes working directly in the to that being detailed for “ Tich,” and also for
frame slots, with hornstavs made from brass the other locomotives recently described in full,
angle. The leading bogie is centrally-sprung, so here we go.
and no turning is needed for the axles. T h e
cylinders have-slide valves, which are operated Frame Assembly
by loose eccentric gear, the outside rocking lever The main frames are cut from 1/16in. or 16-
and the long valve rod taking the place of the full
Walschaerts gear ; but if any reader with the gauge blue steel or galvanised iron, all holes
necessary experience wishes to fit the full being drilled whilst the plates are riveted together
Walschaerts gear, all he has to do is to refer to for cutting to shape. The buffer and drag
the drawings-of “ Doris’s ” valve-gear (the blue- beams are made from 1/2in. by 3/32-angle ;
print obtainable from our offices would be of brass or steel, it doesn’t matter which. Note
great assistance) and make the parts exactly they are different lengths and shapes. The
half-size. Don’t forget to reverse the connections frames are stiffened up by a rod stay turned from
at the top of the combination lever, also to fit the 1/4in. round steel, 1-5/16 in. between shoulders ; and
if this is put in before the frames are attached
return crank to lead the main crank ; otherwise to the buffer and drag beams, it will hold the lot
securely whilst the frames are brazed or silver-
the engine will back up when vou nut the lever soldered into the slots. Braze if steel beams are
in forward position. But for an indoor “ scenic ” used ; silver-solder if brass. The bogie bolster,
railway, you can’t beat the loose eccentric gear. made from 16-gauge steel, or same material
If set to cut off at about 50 per cent., the engine as frames. is tied in uosition with thin iron wire.
will haul a long train on a mere crack of throttle, and braze-d or silver-soldered at the same heating ;
and “keep on keeping on” whilst any water is alternatively, it can be bent up each side to form
left in the boiler. and any spirit in the burners. a flange to go between frames, and riveted in
position with 1/16in. rivets. It is quite possible
The boiler is of the simple water-tube type, that our advertisers may supply -castings for
with a copper-tube barrel and three Averill-type
water tubes, inside a casing which can be made
up from thin sheet steel or iron. Even tin would



THE MODEL ENGINEER NOVEMBER IO, 1949
604 beams, complete with fixing lugs, and a bolster
complete with pin. If so, I advise their use, to
save time. For detailed in structions for cutting
out and erecting frames, see notes about “ Tich.”

Running Gear
The axleboxes are bits of 3/16in. brass 1/2 in.

square, grooved both sides to slide in frame slots,
and drilled 1/4 in. for axles. The hornstays are
1-in. lengths of 1/4in. by 1/16in. angle brass, one
of the angles being filed away at the centre, to
clear the axlebox in lowest position. The spring
pins are 1/16in. silver-steel, or 16-gauge spoke
wire. Fit boxes first, then rivet on the hornstays,
drill the spring-pin hole in middle of same, then
jam each box up against the stay, and drill and
tap it for the pin, through the hole in the stay.
Then there is no chance of the pins binding.
Springs are 22-gauge wire, held by commercial
nuts and washers.

The wheels, axles, coupling-rod pins, eccentrics
and stop collars, are all turned and fitted exactly
as described for “ Tich,” but to the sizes given
in the accompanying illustrations. Be careful
with the quartering of the wheels, on a six-
coupled engine. A couple of short lengths of
5/16in. by1/16in. strip metal, drilled to represent
coupling rods, are of great assistance in getting
the pins exactly right, and the wheels to turn
freely without binding. Note that the driving
and trailing crankpins are not reduced where they
enter the wheel bosses ; leaving them parallel,
saves time and trouble. Put a brass nut over
the thread to protect it whilst pressing in. Leave
5/16 in. of the driving pin projecting from the
wheel boss, and 9/64 in. of the trailing pin.
With the axleboxes blocked up to running
position-that is,with the axle centres 3/8 in.
from bottom of frames-the wheels should
turn freely without binding, or being unduly
slack anywhere, when the dummy coupling-rods
are on the pins. However, don’t press the
second driving wheel right home on the axle
until the eccentric sheaves and stop collars are
fitted ; drawings of these will be given next
week, all being well, along with other details.
I don’t reckon anybody will get as far as the
wheel job in one week !

To save time, I might as well deal with the
proper coupling-rods right away. They are cut
from 1/8in. by 3/8in flat mild steel, either by milling
or sawing and filing, as described for the bigger
engine. Instead of a fork-and-tongue knuckle
joint, an interlocked pin-drilled joint will do well
in this small size ; but the pin must be screwed
into one half of the rod. Simply pin-drill half
of the thickness of each boss, and file off any bits
of metal which project beyond the recess, so that
the two halves interlock, as shown in the section.
Tap the hole in one half 3/32 in. or 7 B.A., and
screw in a bit of 3/32-in. silver-steel. Drill the
other half No. 41 and countersink it. snip
off the pin to length, and rivet over both sides,
leaving the knuckle just free enough to move
when the engine runs over a rough bit of road,
or through switch points and crossing frogs.
There is no need to bush the coupling-rod bosses.
If they wear much, which they shouldn’t do,
even after considerable service, they can be
opened out and bushed when they become slack

THE MODEL ENGINEER NOVEMBER 10, I949
Left-Bogie details

Below-Bogie wheels and
axles

enough to warrant it. The leading boss on each
side is pin-drilled 7/32 in. for half its thickness-
see section-and the crankpin has a flat head to
fit the recess. This pin is screwed into the wheel
boss, instead of being pressed in.

Leading Bogie and is secured by a nut above it. When the
bogie is complete, the other end goes through
The bogie is another kiddy’s practice job. the slot in the centre piece, with a spring and
The side frames of it are cut from 16-gauge washer between, and a nut at the bottom, as
material, same as engine sfhreaemt esm. etTalhecyenatrree shown in the cross-section. It is also quite on
connected by a 16-gauge the cards, that our advertisers may not only
piece I in. wide and 1-5/16 in. long, with a 1/4in. supply cast bolsters with pin complete, which
flange bent up each side, for riveting to the side only need turning and facing, but also cast
centre pieces, with the slot
already in, and which only
it“4- need smoothing off at the
sides, before screwing the
frame plates to them. You
might ‘even be able to get
the side frames and centre
piece all cast in one (like
the pony truck for the 3-1/2in
gitauwgoeu“ldBaonntlaymnCeeodck “) and
drilling
for the axles ; a real “ time-
saver ” !
Plate frames will need
little bronze bushes, turned
from 3/8in. round rod as
per illustration, pressed into
5/16in. holes in the bogie
frames. These take the place
of the conventional axleboxes,

Above-Coupled wheels,
axles and crankpins

Right-Coupling-rods

frames. Alternatively you could, if desired, and are O.K. in this size of locomotive, as the
simply braze a flat plate across the bottom. central spring provides the necessary flexibility.
Whichever plate is fitted, needs a slot 3/16 in. full The wheels are 1-1/8in. diameter on tread, the other
wide, and 3/4 in. long, cut in it for the bogie pin. dimensions being given in the drawing. The
This is a piece of 3/16in. round mild steel I in. axles need no turning whatever, being merely
long, reduced and screwed 5/32 in. by 40 for 2-1/4in. lengths of 3/16in. round mild-steel. Pres s
1/4 in. length at each end. One end goes through one wheel on each axle, poke the axle through
the hole in the bolster on the engine frame ; the bushes, and press on the other wheel, keeping

605

THE MODEL ENGINEER N O V E M B E R 10, 1949
that, without attention of some sort ; also I have
the flange backs 1-9/16 in. apart. The guard-irons yet to make the acquaintance of a blowlamp
can either be cut out separately and riveted on,
or cut in one piece with the bogie frames. Bend which will burn as quietly as a coal fire ! T h e
them outwards, to come over the railheads. loco-type boiler could be fired through a chute ;
Next items, cylinders and valve gear.
and with good quality coal, could run an
Locomotive Details on Other Jobs indefinite time without trouble, noise, nor
Scarcely a week passes without a query fuss.

coming to hand, asking if such-and-such a One of the “ Maid of Kent ” type outside
component, or detail, or method of construction cylinders, with half the valve-gear, would be
which I have described in these notes, can be the berries for a powerful single-cylinder station-
adapted to some other use. Most of them are ary engine ; the complete- “ works ” of an
quite O.K. and straightforward, and easily dealt i n s i d e - c y l i n d e r job, with motion complete,
mounted up on ‘end, would make a fine twin-
with ; but now and then I get either a real cylinder vertical, or even a launch or tugboat
engine. As a matter of fact Mr. Stait, the
teaser, or one which goes from the sublime to father of Dick and Allan of that ilk, who run a
the ridiculous. For example, somebody wanted little “ 0 “-gauge scenic railway at South Cemey
to know what modifications, if any, he would (recollect the story of “ Molly ” and “ Toots,”
have to make to one of my injectors, to make it the “ Mollyette ” sisters ?) built a fine marine
operate under water, like a “ drowned ” hand- engine using two “ Mollyette ” cylinders, with
motion complete, side by side, arranged vertically.
pump in a tender tank ! Maybe a few words on Among all the cylinders and valve-gear arrange-
ments I have described, it should not be difficult
the subject, may save time for both prospective to find one or another, to suit any job within
inauirers and mvself. reason. With my recommended valves, ports,
setting, etc., there would be no question of losing
The locomotive boilers I have described, will efficiency.
do for anything needing a good supply of dry
steam, provided that the boiler can be accom- Pumps and injectors can be selected, from those
modated in the space available. My firebox and I have described, to feed any type of boiler within
tube arrangements will do for any traction engine, reason ; whilst the boiler fittings used on my
portable, semi-portable, undertype, or stationary locomonves are equally suitable for any type of
boiler, and in most cases the full superheating boiler-vertical, horizontal or marine. A fine
arrangements can be used as well. Several of present for a mechanically-minded kiddy would
my wide firebox locomotive-type boilers have be a little steam wagon, with a working steering,
been used for wide-beam steamers, such as small SO that it would run on the floor, around a room.
steam tugs, launches, and similar craft. We A small plain spirit-fired “ pot ” boiler in front,
don’t often hear of coal-fired boilers being adopted the works of “ Mollyette ” under the footboards,
for miniature marine use, yet I don’t know driving the rear axle through three or four gears
whv it should be so. and have often wondered retrieved from a discarded or broken clock, a
why our steamer friends seem to fight shy of coal- little simple “ coachbuilding ” to make a realistic
firing. The boiler of a 2-1/2in. gauge “ Atlantic ” wagon body, and the child would have something
engine, for instance, when in good fettle, will that couldn’t be purchased in any toyshop for
supply enough steam to haul a load equal to
about 30 coaches, for 20 minutes or so at a time, love nor money, especially as things are now I
without touching the fire. I don’t know of any
marine-type blowlamp that will run as long as

Electric Clock with a Semi-free Balance

(Continued from page 600)

“ housing,” clamping the two items together to smear all surfaces of the recess, after warming the
form a template. Remove job from lathe and job with a spirit lamp ; also slightly heat the glass
clear all burrs, etc. Insert three short 12-B.A. disc.
screws and again clamp the two items (cover and
housing) together. Rechuck in lathe and polish (c) Press the disc “ hard in,” applying a
edges of both flanges as one. gentle heat in the meantime. When cool, turn
the wood away sufficiently to expose the edge.
Procure a piece-of 5/64-in. glass and roughly
reduce to a working diameter by " nibbling ” and (d) Turn outside diameter to size, using a
grinding, then proceed as follows :- coarse grade carborundum slip (or diamond tool,
if available) held in slide rest ; do not make it
(a) Mount a short length of hardwood in the fit too tightly into its spigot.
lathe chuck ; face off and-turn a recess sufficiently
large to accommodate the rough disc. (e) Remove from lathe by gently heating and
clean in methylated spirit or other solvent.
(b) With a stick of adhesive (shellac or similar)
606 (To be continued)

Cylinders for the Wee " Dot ” like “Doris ”

by " L.B.S.C.“’

I F anybody cares to tackle a pair of proper any steaming trouble. Better results still, could
piston-valve cylinders for “ Doris’s ” baby be obtained by fitting one of my small oil burners,
sister, all they have to do, is to halve the dimen- blueprints of which are now available from our
sions of the 3-1/2in. gauge pair, and go right ahead. offices. Cylinders of 5/8 in. bore could be used,
If they prefer slide valves, they will find all they if the boiler is fired by an oil burner in good fettle.
need in the way of dimensions, in the accom-
The general instructions for machining and

TAP 8BA LOCATE HOLES
FROM STEAM CHEST

Cylinders for “ Dot ”

panying illustrations. I used a similar pair on fitting the cylinders on the 3-1/2in. gauge engine,
a gauge " I ”engine of the 2-6-0 type, which I can be applied to the smaller one, making
built for an old fellow-conspirator of the railway, variations where necessary. These small castings,
however, need not necessarily be set up on an
now alas ! on the other side of the Great Divide.
angle-plate for boring ; if your four-jaw chuck
Thev were bored out to a shade over 9/16 in.,
as big as the castings would allow ; and the will hold them, use that. The modus operandi
engine ran away with a twelve-year-old boy, is practically the same. If the core-hole in the
on the steam generated by six 1/4in. “ poison-gas ” casting is in the right place, just set it to run
wicks. The boiler was smaller than that I truly ; then face the end flange, bore and ream,
am specifying for “ Dot.” Although I have and finish the other end on a stub mandrel. I f
shown the bores as 1/2 in. in the drawings, it is the core-hole is out of truth, mark a circle on the
quite all right to bore them a little larger if you end, and set it to a scribing-block needle, with
so desire. As long as the chimney liner and the scribing block standing on the lathe bed or
blast nozzle are O.K., so as to get enough air saddle. If beginners haven’t a scribing block,
through the firebox, to ensure complete combus- and finances are well below par, make one up ;
tion-“ take all the poison out of the gas,” as it is easy enough. You would have laughed to
my lamented friend used to say-there won’t be see young Curly’s first attempt at a scribing

639

THE MODEL ENGINEER NOVEMBER 17, 1949
block. The base was a small “ press-in ” type
tin lid ; the spindle was a bit of stiff wire bent but put a piece of I6-gauge or thicker metal,
at right angles at the bottom, and soldered to the such as soft brass or aluminium, between the
lid, the flange of which rested on the lathe bed machined ends and the chuck jaws. Set with a
or whatever was being used. Mother’s flat try-square, same as if you had the job on an
angle-plate. The ports may be end-milled by
iron made a swell “ surface plate ” ! The one of the several methods I have previously

needle was one of mother’s hat-pins. I found described, or be hand-cut wirh a small chisel ;
out how to make the block that carries the needle,
from gazing at a proper scribing block in a tool- if end-milled? it doesn’t matter a bean if the ends
are left semlcircular. The passageways should
shop window ; but mine was very much modified, be drilled by hand, the casting being held in the
bench vice, on the slant, so that if the brace
as I used an old bolt with a wing nut. A hole is held level, it will direct the drill into the side
close to the bolt head, through which rhe wire of the port, and avoid breaking through the
spindle passed, and was clamped by the wing nut, port face.
provided height adjustment, while the hat-pin Covers, Pistons and Glands
was clamped between two washers, placed be-
tween the wing nut and the spindle. “ Where The cylinder covers and pistons are machined
there’s a will, there’s a way,” and “ necessity is and fitted, same as described for the 3-1/2in. gauge
the mother of invention,” were two sayings which job. After mounting the rough-turned pistons
might have been specially inspired by young on their rods, hold the rods in a split-bush in the
Curly’s antics. In later years, I made a good three-jaw, if you haven’t a collet chuck, for finish-
scribing block with a locomotive wheel for a base ; turning the pistons to size. Somebody I know,
and also made vee-blocks by riveting two pieces hadn’t a three-jaw, so he turned the lot between
of sheet metal together and filing to shape, like
centres. If the lathe is a very small one, and
TOP the veracity of the chuck is nothing to
write home about, it might be advisable to
Slide-valve and spindle follow suit. My first tiny lathe didn’t have
you would do to cut out frames, and then fixing any three-jaw, only a few brass chucks of
them (after filing a vee in one edge) at 1/2 in. apart, the kind that unofficial history tells us,
with three little spacers. Incidentally, I wrote were used on the lathe in the engine-room
to a certain party and mentioned these wheezes. of Noah’s Ark ; but I seemed to get on
He promptly wrote an article in which he claimed all right by aid of a few spots of improvisa-

the ideas as his own ; such is life ! Many of tion. I didn’t even have a slide-rest ;

the improvements in small locomotive con- but, as followers of rhese notes who have
struction, as described in these notes, have been read my childhood reminiscences will
recollect, the abnormal physical strength
-and are still being-exploited commercially ; which I possessed when a child, enabled
me to hold a hand-tool perfectlv rigid
not that it worries me in the least, but as our
‘Oxton friend, Bert Smiff would remark, “ Us t for the few simple jobs that I carried
blokes ain’t above a bit o’ scroungin’, but we’re
‘onest enuff to say where we got the goods ! ” through. Incidentally, I’m not exactly a
Nuff sed.
weakling now ; a few days ago, when a
Sometimes these small cylinders are cast solid.
In that case, all you do is to mark out one end friend from Ashford saw me pick up a heavy
and centre-pop the middle of the location of tray of castings by the edge, with one hand, he said
in surprise, “ Curly, you haven’t half got a strong
bore ; chuck in the four-jaw? run the tailstock
wrist ! ” I might add, it takes the two of them to
up to the casting, and adjust jaws until the pop-
mark is true with the tailstock centre. Alterna- carry the 2-6-6-4 Mallet “ Annabel ” down a
tively, you can hold the casting against the flight of stairs, and up a sloping garden path to
tailstock centre, with the point in the pop-mark, our little railway.
and close the chuck jaws down on to it. Put a
1/8in. pilot hole through first, then drill 7/16 in., Beginners note the following : make a dummy
take a cut through with a boring tool, in case the
drill has run out of truth, and finally ream. plug for the stuffing-box in the back cylinder
cover. Just chuck a bit of 1/4in. brass rod in
The casting can be held crosswise in the chuck, three-jaw? face the end, screw for about 1/4 in.
length with 1/4 in. by 40 die in tailstock holder,
for facing off the port face and bolting face ; and part off a slice about 1/8 in. thick. The centre
of this will be automatically marked by the
640 facing tool. Scribe a line right down the middle
of the oval boss, cutting through the centre of
the plug, which should be temporarily screwed
into the stuffing-box. At 9/32 in. above and

below centre, make two centre-dots ; drill No. 48

and tap 3/32 in. or 7 B.A., using drilling-machine
or lathe - not by hand. These holes are for
the guide bars, and if rhey are not dead square
with the cvlinder cover, the bars won’t line up
with the piston rod.

Drill the four No. 43 screw-holes in the cylinder
cover, and put the cover on the end of the
cylinder. Lay the cylinder, bolting face down,

on the lathe bed ; set your scribing-block needle

to the centre of the dummy plug, and adjust

THE MODEL ENGINEER NOVEMBER 17, 1949

the cover until the centres of the guide-bar holes improvisation thereof, as described in the
are at the same height. Put a cramp over the Beginners’ Corner a little while ago-and
cylinder and cover, to prevent the latter shifting, running under a 1/16 in. wide saw-type milling
then run the 43 drill through the holes, making cutter on a spindle between centres. It may also
countersinks on the cylinder flange ; follow with be cut on a shaper or planer, by aid of a 1/16in.
No. 51 and tap 8 B.A. The piston-rod glands parting tool in the clapper box. Alternatively,
a No. 51 hole could be
drilled lonrritudinallv
through the valve, at the
location of the bottom
of the slot ; a saw-cut
made from the top of the
valve, down to the hole,
by aid of two saw-blades
put together in the frame,
and the sides then
smoothed with a key-
cutter’s warding file. Also
a 16-gauge slotting blade
in that most handy
gadget, the Eclipse “ 4s ”
tool, would do the job
in two wags of a dog’s
tail. If castings are
Back view and bolting face of R.H. cylinder used, the exhaust cavity
will be cast in, and the
are turned from 5/16in. hexagon rod, bronze or
gunmetal for preference.

Steamchests valve will be externally to the shape shown. If
Castings for the steamchest will have the bosses cut from solid, file off the corner of the valve
(no need for “ mike ” measurements on that
cast on. Chuck one boss in the three-jaw, and job, even by our old friend Inspector Meticulous.
set the other one to run truly ; centre it with a himself !), and form the cavity by making a
centre-drill in the tailstock chuck. Run up the countersink on the sliding face with a 1/4in. drill,
back centre to support it whilst you turn the and chipping it square by aid of a little chisel
outside,. and face the end of the steamchest ; made from a bit of 1/4in. round or square silver-
then drill it through with No. 41 drill, and open steel. If the length of the cutting edge equals
out and tan 7/32 in. bv 40 for the gland. Reverse the length of the cavity, you don’t get any mouse-
in chuck, repeat operations for ‘the other boss, nibbled edges. Same applies to hand-cut ports.
but drill it right through with 5/32 in. or No. 22
drill, and tap 3/16 in. by 40 for a plug, which is The valve spindles are made from 1-3/4in.
made from a bit of 1/4in. hexagon brass rod. lengths of 3/32-in. rustless steel or bronze rod.
Use bronze or gunmetal rod, if possible, for the One end has a few threads, 3/32 in. or 7 B.A. cut
gland. The steam pipe boss at the side, need
not be turned ; just smooth off the end with a on it ; the other end is filed flat to fit in the slot
file, centre, drill No. 30, and tap 5/32 in. by 40.
Both sides or contact faces of the steamchest in the back of the valve, starting at 3/32 in.
can be machined off with the casting held in a from the end. I usually chuck the spindle in the
four-jaw chuck. three-jaw for screwing, then reverse it, and turn
a couple of scratches with the point of a knife-
Drill the screw-holes ; then cut out a piece tool, at the start and finish of the flattened portion.
One of these (the one farthest from the end,
of 1/16in. sheet brass for the cover-plate, 1-1/4 in.
long and 7/8 in. wide. Drill this by clamping naturally !) is placed level with the chuck jaws ;
the steamchest to it, and using the screw-holes
in same as guide. Then clamp the steamchest and with one of the jaws set to twelve o’clock,
to the port face, and make countersinks on same and the file held horizontally, a flat is formed. The
by running the No. 43 drill through the screw- same jaw is then turned around to six o’clock,
holes. Remove steamchest, drill countersinks and the other flat filed. The length of the flat
No. 51 and tap 8 B.A. Use 8-B.A. countersunk is checked by applying the valve itself to the job.
steel screws to hold the lot together, counter-
sinking the holes in the steamchest cover-plate 641
to match.

Valves and Spindles
The slide valves may be castings, or cut from

a bit of bronze or gunmetal bar, either 3/8 in. by
5/16 in. section, or 3/8 in. square. Hold it in four-
jaw and part off the two lengths to size. The
slots for valve spindles can be best cut, if a
regular milling-machine isn’t available, by
clamping the valve in a machine-vice-or

THE MODEL ENGINEER NOVEMBER 17. 1949
The flats should fit the slots easily, but should in far enough to leave a countersink w h i c h
not have any appreciable end movement, other- measures a full 3/16 in. across. Then turn the
wise the valve setting will be faulty. The fork outside for 1/4in. length, to 1/4 in. diameter, using
on the end of the spindle is made- the same as a knife-tool as when turning wheel seats, and
described for umpteen other engines, so needs screw it 1/4 in. by 40, with the die in tailstock
no detailing. Use oiled paper, or 1/64-in. Hallite holder. You obviously can’t reverse the job in the
or similar jointing, between cylinder casting, chuck, to turn and screw the other end, as the
covers, and steamchest joints ; pack piston and chuck jaws would have to be tightened enough
glands with graphited yarn, and Bob’s your to ruin the threaded part ; so use a tapped bush.
uncle as far as the cylinders are concerned. Next
stage, guide bars, -crossheads, connecting-rods Chuck a short bit of 1/2in. round rod in three-jaw;
and valve-gear.
any odd scrap, brass or steel, about 1/2 in. long,
Beginners’ Corner (contd.). Pump for will do fine. Face the end. centre. drill right
“ Tich ” through with 1/32-in. drill, slightly countersunk
the end with 1/4in. drill, tap 1/4 in. by 40, using the
We left off after finishing the pump barrel and tailstock chuck to guide the tap, as previously
valve-box, so now we need the top and bottom described, and skim off any burr left from drilling
caps for the valve-box. The valves themselves are and tapping. Don’t remove from chuck, but
5/32-in. balls. either rustless steel or phosphor- screw the threaded end of the tee into it. The
bronze. If you are using the former, drop one outer end will run quite truly. Give that end
into the D-bitted end of the valve-box ; rest
the other end on a block of lead, or something a dose of the same medicine as the first end ;
else that won’t damage the faced end. Put a short
bit of 3/16in. round brass rod on top of the ball, and then drill right through it with a No. 40
and give it just one sharp crack with a hammer. drill, as shown in the section of the complete
This takes the sharp arris off the edge of the pump. Make a centre-pop opposite No. I jaw,
reamed hole, and the ball thus forms its own on the bush, before taking it out of the chuck.
watertight seating. If you are using bronze balls,
form the seating as above, with a 5/32-in. cycle Now chuck the casting-by the spigot on top,
bearing ball ; not the bronze ball. The latter provided for the purpose. Set the stem to run
isn’t nearly so hard as the steel ball, and the truly, as above. Face off the end ; centre, and
seating will cut a weeny groove in it, if you try drill it with a No. 40 drill until you break into
to seat it direct. The bronze ball will seat water- the cross-hole at the top. The next bit is where
tight on a seating formed by a cycle ball of similar you need the already-set depth gauge ; turn the
size. stem to 1/4 in. diameter, to the same length as
indicated by the projecting part of the depth
Now take the distance from the top of the ball, gauge pin. Screw it 1/4 in. by 40, and then face
to the top of the valve-box, with a depth gauge; just 1/32 in. off the end, to allow the ball that
Young Curly’s depth gauge was one of mother’s much lift. Finally, file two nicks across the end,
hat-pins stuckthrough a-tram ticket. You can with a thin flat file, so that when the ball rises
make one by drilling a No. 41 hole through an off its seating on the forcing stroke of the pump,
inch or so of 3/16in. square brass rod, putting a and seats against the hole, the water can get
3/32-in. or 7-B.A. set-screw in the side, and out through the nicks. An old friend forgot
using a piece of 3/32-in. silver-steel, about 3 in. these nicks on one of his engines, and spent
long, for the sliding part. Put the rod across the about a fortnight looking for the tight spot,
top of the valve-box ; push the pin down until error in valve-gear, etc., which he imagined was
it touches the ball, and tighten the screw. You’ll causing the wheels to lock as soon as the engine
need this in a few minutes, all being well.
tried to make a start ! Cut off the chucking piece,
The top cover of the valve-box is in the form
of a T, the stem screwing into the valve-box, and file away the stub, making the fitting as neat
and the two ends of the head carrying union
screws for connecting to the boiler clack and the as possible ; then drop the ball in the valve-box,
by-pass valve respectively. It can be made from
a casting, or built up. If cast, it will look like and screw the fitting home, with a touch of
a cross, as it will have a chucking piece on top. plumbers’ jointing (" Boss White,” or any
First, chuck in three-jaw by one side of the head, similar preparation, sold at all ironmongery
and set the other end to run truly, gently tapping stores) on the threads ; but be careful not to
with a lead hammer, or something else that won’t get any inside the valve-box. The union screws
damage the casting, until it doesn’t wobble when should point fore-and-aft, as our nautical friends
the lathe is running. Then tighten the chuck. would remark ; see sectional drawing.
Face off the end carefully ; for nearly all facing
jobs on small fittings, I use a square-ended The bottom fitting is somewhat similarlv
tool, with the point nearest the chuck, ground off machined, but it has only one union screw, and
to an angle of about 30 deg. An ordinary knife- the ball seats on the stem. The fitting will have
tool sometimes catches up and knocks the job two chucking pieces, so chuck in three-jaw by
clean out of the chuck, damaging the soft casting
beyond recall. The tool above mentioned, never one of them ; set the other end to run truly, then
plays rhat trick, and is also useful for chamfering
the corners of union nuts and similar fittings. face, centre, turn and screw it, exactly as des-
cribed for the union ends of the tee above. Then
Centre the end, same as you centred the wheels, drill halfway through it with No. 40 drill. Next,
letting the centre-drill penetrate until it has sunk chuck by the other chucking piece, and set the
end to run truly. Face off, centre, and drill down
with No. 32 drill until you break into the hole
already drilled ; see section of complete pump.
Put a 1/8in. parallel reamer into this hole. as far
as it will go : then carefully face off the end.

Turn the pump upside down, and drop a
5/32-in. ball into the lower part of the valve-box.
Take the distance from the top of the ball, to

642

THE MODEL ENGINEER NOVEMBER 17, 1949
the end of the valve-box as before, and tighten
the set-screw of the depth gauge. Now turn the illustration. Squeeze it in, and silver-solder
stem of the fitting in the chuck, to 1/4 in. diameter, the joint, afterwards cross-nicking it, same as
for a distance approximately 1/64 in. less than the casting.
the length indicated by the gauge pin, and screw
it 1/4 in. by 40. As the ball sinks into the seating a Silver-soldering Fittings
little, this will give the ball a shade over 1/32 in. This is one of the easiest jobs going. I use
total lift. Saw off both chucking pieces, and
smooth the stubs away with a file ; put the ball “ Easyflo ” silver-solder in wire form (supplied
(if steel) on the end of the stem, apply the brass commercially by Johnson-Matthey’s) and the
special flux that goes with it ; but best grade
silver-solder cut in thin strips, with jewellers

Built- up pump fittings Simple depth gauge

rod to it, and give it a crack with a hammer as borax (powdered and mixed to a paste with water)
above. The fitting can be held in the bench vice does very well. You can use a little blowlamp,
for this job. Then drop the ball in the hole in or a small gas blowpipe can be made in a few
the valve-box, and screw in the fitting, with the minutes from a bit of 3/8in. brass or copper tube,
union screw pointing towards the pump barrel, which is self-blowing. See illustration, which
as shown in the section of the complete pump. explains itself. A small tin lid with a few bits
of small coke or asbestos cubes in it, makes a
Built-up Fittings small forge ; it need not be bigger than a soap
Instead of using castings, the top and bottom dish. Simply anoint the joint with the wet flux,
blow to medium red, and touch the joint with the
fittings may be built-up. For the top one, chuck silver-solder wire or strip. It immediately melts
a piece of 5/16in. round brass rod in the three-jaw. and runs m. Don’t use too much-it not only
Face the end, centre deeply, and turn and screw spoils the appearance, but is expensive. Quench
it exactly as described for the casting ; part off out when it has cooled to black, in a drop of
at I in. from the end. Reverse in chuck, and acid pickle in a jam jar. The acid pickle is
serve the other end the same, drilling a No. 40

Facing and chamfering tool Simple self-blowing gas blowpipe

hole clean through. Drill a 5/32-in. hole in the composed of I part commercial sulphuric acid
side, halfway along, breaking into the middle hole. to about 16 of water, or I part old accumulator
acid to 4 of water. Let the fitting stay in for
Chuck a piece of Q-in. brass rod in three-jaw ; about ten minutes, then fisli it out, wash under the
face, centre, and drill down 3/4 in. depth with No. kitchen tap, wipe dry and clean up. For cleaning
40 drill. Face off the end until any countersinking up, I use a circular wire brush on a spindle
has been removed ; then turn the end to 1/4 in. stuck in a taper hole in the end of my electric
diameter, to 1/32 in. less than distance from top grinder ; but it does as well if held in the lathe
of ball to top of box, as indicated by the depth chuck. Run the lathe as fast as possible without
gauge. Screw 1/4 in. by 40, and part off at 5/8 in. causing an earthquake.
from the end. Put the tapped bush in the chuck,
with the centre-pop opposite No. I jaw, and screw The bottom fitting is easier still to build up.
the fitting into it. Turn 1/16 in. of the end, to a Simply chuck a bit of 3/8in. brass rod in three-
tight fit in the side hole in the other piece ; jaw, and proceed to machine up the end exactly
then turn the rest to the shape shown m the
(Continued o n next page)
143

The Murad " Cadet” 4-in. Lathe

Messrs. Murad Developments Ltd., of Stock- tray, with machined seatings for the feet of the
lade, Aylesbury, Bucks, have recently introduced lathe, serving to increase its rigidity and further
a new 4-in. lathe which embodies several inter- resist distortion. The electrical equipment con-
esting features. It has a centre height of 4in., sists of a 1/2 h.p. motor bolted to the back of the
with a gap bed, admitting a maximum diameter stand and driving the enclosed gear counter-
of II in. in the gap, and maximum length of shaft by vee-belt, also a built-in motor reversing
18 in. between centres. The headstock has an switch below the headstock. Standard equip-
all-geared drive, giving six speeds from 43 to ment includes driver plate, two centres, set of
818 r.p.m. and the mandrel, which has a through change gears, and necessary spanners ; extras
bore of 13/16 in. with No. 3 Morse taper socket, include 8-in. faceplate, fixed and travelling
runs in large-diameter, long white metal bearings. steadies, independent and self-centring chucks,
The standard set of change-wheels provides for chasing dialj 4-way turret toolpost, and
cutting threads from 2-1/2 to 96 t.p.i., and saddle collet attachment. A l o n g b e d m a c h i n e ,
feeds from 0.400 to 0.0037. taking 24 in. between centres, is also available
to order.
A cast-iron stand is supplied, and also a cast

“ L.B.S.C."

(Continued from previous page)

as described for the casting, when forming the in the notes in August 25th issue, in which I
ball seat. Part off at 5/16 in. from the shoulder, said, erect the pump stay level with bottom of
and drill a 5/32-in. hole in the side. Chuck a frame. It should be placed 1/16 in. above the bot-
piece of 1/4in. round rod in the three-jaw ; face tom, so as to line up the pump barrel with the
the end, centre deeply, and drill down to a full centre of driving axle in running position. Most
1/2 in. depth with No. 40 drill. Screw the outside builders put it thus. as the position of the screw-
1/4 in. by 40, for1/4 in. length, and part off at 3/8 in. holes gave the necessary clue ; but if anybody
from the end. Rechuck in the tapped bush ; has put it level with the bottom of the frame, it
turn about 3/32 in. of the end to a tight squeeze doesn’t matter a bean. As the distance between
fit in the side hole of the other part. Squeeze the eccentric-strap centre, and the eye in the rod
it in, silver-solder it, pickle, wash and clean up. is 2 in., the 1/16 in. offset won’t affect the working
Seat a ball on the faced end, and assemble as of the pump in the slightest. I just mixed up
previously explained. the pump for “ Tich ” with one I schemed out

May I beg your forgiveness for a small error for another engine !
644

A Wee " Dot ” like “ Doris ”

by “ L.B.S.C.”

THERE is no need to bother about filing can be end-milled out, same as axleboxes, or
up a posh pair of specially-shaped guide-bars cut on a planer or shaper, with a parting-tool
for each cylinder in this small size. The kind a full 1/8 in. wide, in the clapper box. If you set
shown, look all right, do the job, and are easy your slide-gauge to the same distance between
enough to make. All you need are four pieces the jaws, as the guide-bars, the right depth of
of 3/32-in. by 1/8in. silver-steel, each 2 in. long. groove is easily obtained. Cut the grooves each
Chuck each truly in the four-jaw, turn down 1/8 in. side of the piece of metal first; then chuck
of one end to 3/32 in. diameter, and screw truly in four-jaw, turn and drill the bosses,
3/32 in. or 7 B.A. to match the tapped hole in mark off and pin-drill the backs. then saw or
the gland boss on the part off the piece in the
cylinder cover. Then middle, and finish with
bevel off the outer ends a three-cornered file, A
with a file, as shown. good way for beginners
Tip to beginners : screw to drill the bosses, is
each guide bar into to mark them in place,
the gland boss before using the cylinder cover
filing the bevel. If you for a jig. Take off
don’t it’s a million dollars the cover, put the cross-
to a pinch of snuff, Guide bars head between the bars

FRONI CROSS L O N G SECTION
SECTION
Crossheads

that the guide-bar will seat home with the and run it right up to the gland. Hold it there
bevel upside down-such is the general cussed- with a toolmaker’s cramp, and poke a No. 30
ness of things in this benighted world-and when drill through the stuffing-box and gland, making
you attempt to get the other half-turn? bing goes a countersink on the boss of the crosshead.
the end of the screw, and you’ve had it ! Either Remove the crosshead, and drill out the counter-
file the bevels with the bars in place-I have no sink with No. 31 drill, either on a drilling machine,
trouble in gripping the ends of the bars in the or by chucking the crosshead in the four-jaw
bench vice-or mark which is top and bottom, again with the countersink running truly.
take them out, file the bevel, and replace. If Don't pin the crossheads to the piston-rods
the holes in the bosses have been truly drilled until the connecting-rods have been made and
and tapped, and the ends of the bars screwed fitted.
with the die in the tailstock holder, both bars
should be parallel with the piston-rod when Guide Yokes or Motion Brackets
fully extended, and the bars screwed home. If The brackets for supporting the guide-bars
not, they will stand a weeny bit of coaxing, but
may be little castings of the same pattern as used
not much ; so watch your step ! on the 3-1/2in. gauge engine, or cut out of 3/32-in.
steel. In the former case they only need cleaning
The crossheads differ from the 3-1/2in. gauge up with a file, and drilling for the screws. Plate
size, in being of the single-sided pattern, very brackets may either have the attaching flange
easy to make and fit. No need to carve them out bent up from the self-material, or have a bit of
of solid steel for a gauge “ I ” engine. A bit angle riveted on. Don’t forget you need one
of nickel-bronze (German silver) would do, or right-hand and one lee-hand. The illustration
ordinary bronze or gunmetal ; it can easily be gives the sizes, so no further explanation is
tinned over, if you are scared of our old friend necessary. The brackets also are erected after
Inspector Meticulous. A piece of 9/16in. by the connecting-rods are fitted, and these form the
1/4in. section, or nearest larger, about 1-3/8in. next job.
long, will make the pair of them. The grooves
663

THE MODEL ENGINEER NOVEMBER 24, 1949
Connecting-rods rods are attached to the cylinders, they are ready

The connecting-rods can be milled, or sawn for erection ; but if you are using the recom-
and filed, from 1/2in. by 1/8in. flat mild-steel, the
sizes being shown in the drawing. The little- mended loose eccentric valve gear, wait until the
end doesn’t need bushing, though it might be eccentrics are assembled on the driving axle,
case-hardened, if anybody likes to take the and the wheels pressed on “ for keeps,” before
trouble to do it. Just heat to red, roll the eye attaching them to frames.

Rocking shaft and levers Eccentrics and Stop Collars
in any good case-hardening powder, such as The eccentric sheaves, or tumblers, are turned
“ Kasenit,” “ Pearlite,” etc., filling up the hole.
Reheat until the yellow flame dies away, then from 3/4in. round mild-steel held in the three-
quench in water, and clean up. The big-end jaw ; another simple job. Aim for the smoothest
should be bushed, as it has to stand the whole possible finish. The toohnarks will indicate the
driving stress, so drill the hole 3/16 in., and turn
up a bush for each rod, from 1/4in. round bronze. true centre ; and if a line is scribed across it,
This should, when pressed home, stand just
proud of the back of the rod ;1/64 in. is plenty. what Pat would call the “ eccentric centre,”
The outside flange should stand out 1/32 in. and the hole for the stop pin, can be set out on it
as shown. There is no real need to drill an as shown. Beginners would do well to-chuck the
oil-hole, but it looks better with one ; also, the eccentric in the four-jaw, with the pop-mark
driver might go on strike if there is nowhere on for the axle hole running truly, and drill and ream
the big-end to poke in the spout of his beloved with the necessary weapons in the tailstock chuck.
The eccentrics only need to wobble up and down,
oil-feeder ! Incidentally, if some motorists I not sideways ! Also, the fit of the sheaves on the
axle, should be as close as possible, consistent
know, took the same interest in their oil feeders,
and used them as we did, there wouldn’t be such with freedom to turn. They must not be sloppy ;
a lot of rattling steering-gears, wobbling wheels,
and so on ! You don’t find any dry pins and bushes one of my correspondents had a gauge “ I ”
under the leading end of my gasoline buggy, or engine with loose eccentric gear, and “loose”
anywhere else on her, if it comes to that. The described it exactly. He complained that it kept

REAM I No43 DRILL
1/8"
; ‘7
Rocking shaft bearings
garageman down at the end of our road-who, J
incidentally, owns an “ inch-scale ” Stirling
eight-footer-says that a few more clients like Guide-bar brackets
your humble servant, would land him, not in the on “ seizing up ” when running, and had eased
every blessed thing on it that could possibly be
workshop, but in the workhouse ! eased. I had to grin when I saw it, and stopped
the “ seizing up ” in a few seconds by merely
The connecting-rods are attached to the cross-
heads by special large-headed pins turned up tightening the valve spindle glands ! What was
from 1/4in. round steel rod, to the sizes given in
the illustration ; this needs. no detailing out. happening was that the motion work was so loose
When the guide-bars, crossheads, and connecting- and sloppy, that when the engine was running
664 slowly, as soon as each eccentric passed the top
centre, the weight of the tumbler and the strap
caused it to fall down in advance of the stop pin,
shutting the port and “ stopping the clock.” The
bit of extra friction caused by tightening the
spindle glands, was just too much to allow the
eccentric to operate the valve without being
pushed by the stop collar. The stop pins in
the present eccentrics are bits of 3/32in. silver-
steel squeezed into No. 43 drill holes.

The stop collars are simply 1/4in. slices of 3/4in.
rod (brass or steel) with a segment milled, planed,
or sawn and filed away as shown. Drill a No. 48
hole in the thick side, and tap 3/32 in. or 7 B.A.
for a set-screw. I wonder if those good folk who
raise objections to set-screwed eccentrics, stop

THE MODEL ENGINEER NOVEMBER 24, 1949
collars and so on, know that this
has often been done in full-size 1 H ROD SHOWN BROBNUZSEH
practice. Many locomotives have
their eccentrics set-screwed to the Connecting-rods
axle, the screws having “ cupped
points ” (says Pat) which are long, on the end of a bit of 1/4in. by 40 rod held in
hardened, and when they are three-jaw. Screw it 3/16in. by 40, and part off about
screwed home, they bite into the ec3rx/oh1sa6shuiesnat.dfproipmaentdhhoelsehcooinnunldetchetrei.n‘ Sgcc-rryoeldwin, dtheriss.liidnetAotttathhcehe
soft steel of the axle so deeply guide-bar bracket over the bars, and put
that there is no earthly chance of the whole issue in place against the frame
any movement. The holes into with the brass plug going through the 1/4in.
which the heads are sunk, are exhaust pipe hole in the frame. Pull the piston-
then filled up with white metal, rod out as far as it will go, and line it up with the
flush with the rubbing surface of centre-line of motion. If you haven’t got this
the sheaves, and thus it is also marked on the frame, don’t let that worry you.
impossible for the set-screws to slack back. I’ve Get a bit of sewing cotton, stretch it tight, and
done the same thing with slotted screw-heads in hold it above the centre-line of the piston-rod,
small eccentrics, and never had one shift yet, all parallel with it, full length. If the other end of
the years I have been locomotive building. the cotton passes across the centre of the driving
axle in running position (3/8 in. from bottom of
The eccentric straps are castings ; don’t forget frame), the cylinder is set O.K. If not, simply
adjust the cylinder until you get it right. Then
to saw them across, using vice top as guide, and put a toolmaker’s cramp over the cylinder and
screw the halves together before boring to fit the frame, poke a No. 34 drill through the holes in
tumblers. Here again, they should fit easily both frames at once, making countersinks on the
bolting face ; remove cylinder, drill counter-
+___ ,&----_i! , sinks No. 44, and tap 6 B.A.

“-Fb ++. Put a couple of 6-B.A. screws in, to hold
cylinder temporarily. Set the guide-bar bracket
Eccentric straps and rods in position shown in illustrations, and attach
it to frame by three 8-B.A. screws. This size
without shake. The rods are filed up from 1/16in. is better than 3/32 in. or 7 B.A. for many jobs ,
by 5/16in. mild-steel strip, and riveted and soldered as the thread is just as strong, but the heads
into grooves in the lugs monaktehenostbrbayps.rivBetists are smaller ; however, if you haven’t any, just
domestic blanket pins foorf make use of what you’ve got. Now push the
jobs like this ; drill the holes a tight fit for the piston-rod bang up against the front cylinder
pins, and countersink both sides. The eyes can cover, and put the crank on front dead centre.
be case-hardened if you so desire. The boss of the crosshead will go over the end
When assembling the eccentrics on the driving of the rod. Advance the rod another 1/32 in.
axle, note that the flange goes up against the into the boss, and pm boss to rod with a bit of
axlebox, and the gap in the stop collar goes over 1/16in. silver-steel or 16-gauge spoke wire,
the driving pin ; see plan view of the whole box squeezed into a No. 52 hole drilled through boss
of tricks. The driving and rod.

wheels can then be
quartered, squeezed
home, and the coupling
rods erected for
keeps.”

How to Erect Cylinders

About the easiest Loose eccentrics and stop collars
way I know for a
beginner to erect little
cylinders on an engine
like this, is to turn a
3/16in. pip about 1/8in.

THE MODEL ENGINEER NOVEMBER 24, 1949

Rocking Shafts for Valve-gear How to Assemble the Valve-gear
The movement of the eccentric rod is trans- There is nothing difficult about assembly and

mitted “ upstairs and outside ” by a little rocking erection. Pin the leading end of the valve-rod
shaft with opposed levers ; see illustrations. to the fork on the spindle, by a bit of 3/32-in.
The bearings for each of these, fits into the silver-steel turned down each end to 1/16 in.,
1/4in. hole in the frames, between the leading screwed either 1/16 in. or 10-B.A. and furnished
coupled and driving wheels. To make one, with nuts. The back end goes over the pin
just chuck a bit of 5/8in. round rod (bronze or in the rocker-arm and is nutted, the rocker-
gunmetal) in three-jaw, turn down 3/8in. length shaft being put through the bearing from out-
to 1/4 in. diameter, and part off 1/8 in. from shoulder. side the frame. Put the eye of the eccentric

+
,

1

t 3/32"

Reverse in chuck, centre, drill through with rod in the slot in the inside rocker-arm,
No. 34 drill, and ream 1/8 in. File the flange and secure it with the special screw. This
oval, as shown. At 3/32 in. above and below the should be done with the arm and eccentric-
1/4in. hole in frame, drill a No. 43 hole and rod off the engine, so that the end of the
countersink it. Put the flange in place from screw, which should project a weeny bit, can
inside the frame, and secure with a couple of be slightly burred over, to prevent it coming
8-B.A. countersunk screws, as shown in the adrift when the engine is at work. This is
cross-section. necessary, as there is only 1/16 in. of thread to
keep the screw in place, and we can’t locknut
The shaft is a 3/4in. length of 1/8in. round silver- it on account of the flange of the rocker bearing
steel. The outside lever is filed to shape from getting in the way. Put the rocker-arm on the
any odd bit of 1/16in. steel, the larger end being end of the shaft inside the frame, and put the
drilled and reamed a tight fit for the shaft, to strap on the eccentric tumbler, securing it with
which it is brazed or silver-soldered. The small the screws through the lugs as shown. If the
end carries a 3/32-in. pin, screwed in and riveted set-screw in the stop collar is tightened, ditto
over at the back. The inner arm is 3/16 in. the temporary one in the inside rocking-lever,
thick, and is slotted, as shown, to accommodate and the wheels turned by hand, the stop collar
the eccentric-rod eye. One side of the slot is should catch the eccentric pin against one
drilled No. 41, and the other tapped 8 B.A. to of its shoulders, and operate the gear easily
take the special pin shown in the drawing ; this and smoothly in either direction of rotation
can be turned up from a bit of 3/16in. hexagon of wheels.
steel, or the pin may be cheese-headed, just as
you fancy. Put a temporary 8-B.A. set-screw in How to Set the Valves
the thick end, to clamp the arm to the shaft I usually set my valves under pressure, but

whilst valve-setting ; when the valves are O.K. for beginners and other inexperienced workers,
the valves are set easier by sight. Take off the
it may be pinned. steamchest covers, and turn the wheels by hand.
The valve should uncover both ports an equal
Valve-rods amount at each end of the movement. If
If there’s one thing I love to see, more than it doesn’t, all you do is to move the inside arm
on the spindle, one way or the other, until you
another, in any little locomotive, it is a valve- get equal port openings, and then tighten up
gear with straight rods ; but in the present case the set-screw. For this job, the stop collars
we can’t have a straight valve-rod, because the may be tightened in any position.
outside rocking arms can only extend 3/8 in. from
the frames, otherwise. the coupling-rods would To set valves, put one of the main cranks on
hit them. The coupling-rods clear the rocking front dead centre, with the piston-rod in as far as it
levers by just 1/32 in., which is quite close will go. Loosen the corresponding stop-collar
set-screw, and give it one turn in the forward
enough ; but the valve-rods are high enough to direction, to make certain it is driving the eccen-
tric properly. Watch the valve closely. Note
miss. They are milled, or sawn and filed, from when it goes as far towards the front of the steam-
3/16in. by 1/16in. mild-steel strip, to the dimen-
sions given in the illustration; note, the length chest as possible ; then, as it comes back, look
between the pinhole centres should be 3-1/8in.
after the rod has been offset 9/32 in. as shown. for a black line at the edge of the valve lap,
If you allow about 1/64 in. extra on the straight
rod, it will be all sereny after setting.

666

THE MODEL ENGINEER NOVEMBER 24, 1949

denoting that the front port has just “ cracked ” Three views, showing
as the enginemen would say. Tighten the arrangement of valve-
set-screw in the stop collar, when this state of
affairs is reached ; then turn the wheels in the gear
forward direction until the back port cracks.
If the crank is exactly on back dead centre, the is just nobody’s business ; and I’ve never had a
valve is right length, and the setting correct for shifted eccentric in a link motion, or inside
forward gear. However, if the crank has not Walschaerts gear. Well, that settles the cylinders
reached the dead centre, the valve is too short, and motion ; now we want some steam to drive
and if the crank has passed the centre, it is too them, and a drop of oil to help them do the job ;
long. The first can best be remedied by a so, all being well, the next instalment will deal
fresh valve ; the second, by taking a shade off with boiler, pipe work, and lubricating and
both ends, so as to keep the cavity in the exact firing arrangements.
centre of the valve. This is very important.
After shortening, readjust the stop collar, so as Rusty Cylinders
to get the valve just cracking each port on the
dead centres. Mention above of doing jobs for friends, calls
to mind an overhaul I carried out for an old
Now turn the wheel backwards, so that the friend just before Hitler lowered the boom, as
other shoulders of the stop collars engage the Pat would remark. The engine had cast-iron
pins in the eccentrics, and watch the valve again. cylinders, with pistons and valves made from
a special brand of nickel-iron used in automobile
Trial and Error work. If our worthy brother who said that he
If the ports crack on each dead centre, as had never seen a properly-rusted cylinder, had
seen what I saw when I dismantled the engine,
before, the setting is correct for both directions, he would have dropped down in a dead faint.
and the job is done. If the ports crack before The bores were all pitted, and the port faces
the crank reaches dead centre, take a weeny bit were very much like caratcelross.e-upHapdhoittonootfbethene
off the stop collar shoulder with a little chisel, moon, complete with
home-made from a bit of silver-steel. If the for the fact that special patterns would have
ports do not crack until after the drank has been needed, to replace the cylinders, I would
passed dead centre, make up the stop collar by have substituted a bronze pair. As it was, I
soldering a little bit of brass to the shoulder. had to machine a full 1/16 in. off the port faces,
It is merely a question of trial and error. In before getting a smooth surface ; and to prevent
days gone by, when I was able to do a few repetition of the rusting, I made and fitted
jobs for friends, in the way of repairs and over- separate hard bronze port faces. The cylinders
were bored out as big as the castings would
hauls, I sometimes found one opening late ; allow, and bronze liners fitted. The new valves
and pistons were made from a sample of metal
and easily found out the thickness of packing something like monel, sent by an American
needed, by putting test strips of different thick- friend. Like “ Soplue Tuckshop ” oIf’vrea dhai od
nesses between the shoulder of the stop collar fame, the engine is “ all right now.”
and the eccentric pin, like using a feeler gauge. plenty of experiences with small cast-iron cylin-
When both front and back ports crack on the ders-and experience still teaches !
corresponding dead centres, when turning the
wheels either forward or backward, the valve-
gear and setting are O.K., and you can tighten
up the set-screws in the stop collars “ for

keeps.” Don’t be afraid of them shifting ;

because, despite the moans raised about set-
screwed eccentrics, I’ve never had any trouble
with them in any engine in my own “ running-
shed.” The gallons of water that set-screwed
eccentric-driven pumps have put into the boilers,

667

EFORE making and fitting the boiler, we A Wee "Dot"
shall need the steam and exhaust-pipes, and
the lubricator, so make these the next job. The by “ L.B.S
exhaust-pipe assembly should be fitted first.
The centre part of this is a 1/2in. length of 5/16in. piece of 1/2in. copper or brass tube about 22- ,
square brass rod, drilled 5/32 in. right through, gauge, with two discs of 18-gauge copper silver-
and tapped 3/16in. by 40 ; an easy job in the
four-jaw chuck. In the middle of one side, soldered in the ends ; it should just fit between
silver-solder an inch of 3/16in. copper tube;
screw the end 3/16 in. by 40 and fit a blast nozzle the frames. The valve is made from a 15/16in.
made from 1/4in. hexagon rod, with a 3/32-in. length of 3/16in. brass rod, with a valve pin of
hole in it. The cross pipes are 3/4in. lengths of 3/32-in. rustless steel or bronze, 1/4in. wheel,
3/16in. copper tube, screwed as shown in the and 5/32 in. x 40 gland. The filling plug is
illustrauon, and furnished with lock-nuts. 3/16 in. x 40, hexagon head, with a bush to match,
Beginners note: to erect, all you do is to screw which is silver-soldered into the tank, above
the cross-pipes into the tee until they touch,
place the assembly between the cylinders, in

Boiler for Wee “ Dot ” like “ Doris ”

line with the exhaust holes, and screw the pipes the valve. The drain-pipe for condensate water
out of the tee, into the tapped holes in cylinders, is just a piece of 1/8in. copper tube long enough to
reach to the buffer beam as shown ; valve, bush,
until the short thread is right home at each side ; and drain pipe are all silver-soldered at one heat.
The lubricator is screwed to the stem of the tee,
then tighten the lock-nuts against the tee. and the whole bag of tricks placed in position
The steam-pipe assembly is on the same as shown. The steam-pipes are run out of the
tee into the bosses on the steam-chests, and the
principle ; but the tee is horizontal, the steam lock-nuts run back against the tee ; anoint the
connection is on top of the stem, and the lubri- threads on the pipes with plumbers’ jointing
cator at the end, the whole issue forming one before erecting. A screw run through each
unit. The tee may be a casting, or cut from a frame, into each end of the lubricator, prevents
piece of 1/2in. x 5/16in. brass bar, the unwanted it falling down. If an adaptor is made to suit
part being sawn away. The head is drilled and a motor tyre pump, and temporarily screwed on
tapped right through, 5/32 in. x 40, in the four- to the bit of 5/32-in. pipe on top of the tee, the
jaw ; the stem is drilled up 5/32 in. to meet the “ works ” can be tested by air pressure. T h e
cross-hole, and the end tapped 3/16 in. x 40 for wheels should turn equally well in either direction,
the lubricator. At 1/2 in. from the centre of the you can gauge’ the power by holding a wheel
head, silver-solder in a piece of 5/32in. copper with your fingers. A vigorous stroke of the
tube about 3/8 in. long, screwed 5/32 in. x 40 pump will probably snatch it away ; whilst
for half its length. The cross-pipes are made if the chassis is placed on the floor, one or two
and fitted, same as the cross-pipes for exhaust, strokes should send it careering across the
except that they are 5/32-in, with smaller lock- workshop.
nuts-to suit.

The lubricator is a simple displacement affair
with a weeny regulating valve. The tank is a
16

" like " Doris ” tubes are put in on the late Mr. T. W. Averill’s
method, with straight front ends. For beginner’s
B.S.C." benefit, you just drill the three holes, poke a
bit of 5/32-in. steel rod, in each, and force it
Boiler down to the angle shown for the tubes. This
The outer casing of the water-tube boiler is distorts the hole in the barrel, sufficiently for
the tubes to be inserted. Note the bends at
similar to that specified for “ Doris,” made to the rear end are 90 deg. only ; not the acute
the given dimensions. In this little engine, bends which you see on commercial engines
there is no need to slope the firebox wrapper with this type of boiler. Fit the bushes for
filling-plug under dome, for safety-valves, and
back ; leave it parallel, then one former will do for footplate fittings, then silver-solder tubes
and bushes at one heat.
for throatplate and backhead. The best stuff
to use for the wrapper would be sheet steel of Boiler Fittings
about ao-gauge ; this doesn’t conduct heat The boiler fittings are cut down to the mini-

mum. In addition to the filling-plug and safety-

--t’-+

REGULATOR
GLAND. BLOWER VALVE

WATER
LEVEL
TEST
VALVE

DRAG BEAM. ’ TO UNDERSIDE
OF FOOTSTEP

Arrangement of backhead
fittings

away like brass, though the latter can, of course, valves, we need just a regulator, blower, feed-
be used if preferred. The smokebox may be clack, test-cock, and step-gauge. No water
either a bit of 2-in. tube, or rolled up ; doesn’t gauge is required ; a few strokes of the hand-
matter which ; it is attached to the boiler case, pump every three or four minutes, will maintain
after the inside barrel has been fitted, by a water level. Even if the boiler runs dry, it
“ piston-ring ” joint. The taper part of the doesn’t matter a bean ; the heat from a “ poison-
boiler is easily rolled up, with a 3/16in. lap seam gas plant ” cannot hurt a brazed boiler of this
underneath, secured by a few 1/16in. rivets; type, neither will it hurt if you pump water in,
no need to braze it unless you wish. The firebox although the pressure-gauge needle will get a
wrapper is bent up as described for “ Doris,”
the throatplate being flanged, and secured by a bad shock on the first stroke or two ! These
few rivets. The large end of the barrel is simply
placed over the hole cut in the throatplate, and tiny boilers will stand more “ rough-housing ”
brazed, the joint between throatplate and wrapper than big ones.
being filled in with brazing material same time.
The holes for dome and safety-valves are cut, The regulator is nothing more than a glorified
as shown in the illustration. screw-down valve, with a body as long as a
Jerry poodle, this being made from a piece of
The backhead is knocked up from 16-gauge 1/2in. hexagon brass rod measuring 3-5/16 in. long,
copper sheet. The inside barrel, which is a
9-in. length of 1-5/8-in. x 22 or 20-gauge seamless after both ends have been truly faced. Centre
copper tube, is brazed to it, the outer end being
closed by a brazed-in flanged disc of 16-gauge each end, and drill down with No. 30 drill until
copper. The three 5/32-in. x 22-gauge water- the holes meet in the middle and form a thorough-

fare. Turn down 3 in. length to 5/16 in. diameter ;

beginners-and anybody else whose lathe is a
bit “ off colour “ had better do this job between
centres. Then further reduce 2-3/4 in. length to

17

THE MODEL ENGINEER JANUARY 5, 1950
9/32 in. diameter, and screw the odd 1/4 in. Put a taste of plumber’s jointing on the external
5/16 in. x 32 or 40. Hold the hexagon end in thread, and on the steam pipe threads ; then
the three-jaw, and run up the tailstock until the when the elbow is screwed home as shown, there
centre point enters the hole in the round end. will be no chance of steam leakage The super-
Then, if you screw the chuck iaws tightly down heater loop is attached to the nipple by a nut
on the hexagon, and pull the tailstock away, and cone the length of the loop being approxi-
the “ dog’s body ” part should run truly. Open mately 22 in. It runs back along one side
it out to I in. depth with a 9/64-in. or No. 27 between boiler and casing, passes between water-
drill, and tap it 3/16 in. Whitwonh ; the coarse tubes and barrel as shown, returns along the
thread gives the regulator a quick action. other side. and terminates in a swan-neck, which
Starting at 7/32 in. from the end, drill three will be attached by a union fitting to the little

TO JET IN
SMOKEBOX.

No.40 I
DRILL -I

Blower-valve assembly “y$._

Water level test-valve

1/16in. holes close together, as shown., clearing vertical pipe on the steam tee, when the boiler
out any burrs by running the tap in again. Hold is erected. The arrangement is shown in the
the barrel part in three-jaw, and turn down the longitudinal section of the boiler.
hexagon end to 1/4 in. diameter, screwing for the
gland-nut as shown, leaving enough hexagon to I have described in full detail, how to make
form a spanner hold when screwing the regulator screw-down valves, clacks, and other etceteras
into the backhead bush. so many times, that there is no need to go into
the whole’rigmarole for this job. Anyway? the
Turn up a nipple for the tapped end, from illustrations of the backhead fittings are’practncally
5/16in. brass rod, as shown ; this must be faced self-explanatory. The blower-valve takes steam
truly at the spigot end, to form the seating for from a connection on the barrel about 1-1/4 in.
the valve pin. This merchant is made from a from the backhead. This is a little block of
bit of 3/16in. rustless steel or bronze rod held 1/4in. square brass rod, with a spigot turned on it,
in three-jaw. Turn down 5/16 in. length to 1/8 in. to fit a 3/16in. hole drilled in the barrel. Drill a
diameter, and form a cone point on it ; beginners 1/8in. hole in one of the facets, and drill No. 40
note that this may be done by a few strokes of a through the spigot, to meet the other hole ; then
fine file, swept across the end of the rod with the put the block in place. Fit a union nut and cone
lathe running fast, holding the file at the right to a bit of 1/8in. copper tube about 1-3/4 in. long.
angle to suit the cone. Screw the next 5/16 in. Drill a No. 30 hole in the backhead just above
length with 3/16in. Whitworth die, and part off.
Reverse in chuck, centre, and drill in a little way the barrel ; poke the end of the tube through it,
with 1/8in. drill. Drive a bit of 1/8in. rustless
steel or bronze rod into the hole, and silver- and enter it in the block. Silver-solder the
solder it. The outer end has a square filed on block to the barrel, and the tube to the block, at
it for the regulator handle (I have shown L.M.S.
pattern, but any kind you fancy will do equally the same heat ; with the thin metal, a direct appli-
well) and reduce the extreme end to 1/16 in.
diameter, screwing 1/16 in. or 10B.A. for retaining cation of the blowlamp flame will do the trick.
nut. The sectional illustration shows how to Make up a blower-valve as illustration, and silver-
assemble the whole bag of tricks ; screw a 6-in. solder a piece of 1/8in. copper tube into it, about
length of 5/32-in. copper tube into it, both ends 11 in. long ; the outer end of this should be
of the tube being threaded, and screw the screwed 5 B.A. Drill and tap a 1/4in. by 40 hole
regulator into a bush, tapped to suit, silver- in the top right corner of the backhead ; poke
soldered into the backhead at the position shown, the long pipe through it, and screw the valve
The other end of the pipe should just be showing home, the nipple on same being set horizontally.
through a 1/4in. x 40 hole in the plate at the front Bend the end of the blower pipe around to meet
end. it, and couple up. Fit a weeny nozzle on the
outer end, with a No. 70 hole in it, and set it
The front end elbow is a 5/8in. length of 3/8in. alongside the blast nozzle, so that the jet of steam
brass rod, with a 1/2in. deep hole in it, drilled will blow up the chimney liner. If it won’t “ stay
No. 30 and tapped 5/32 in. x 40 for the steam put,” tie it to the blastpipe with a bit of thin wire.
pipe. The end is reduced to 1/4 in. diameter for
3/16 in. length, and screwed 1/4 in. x 40. A 1/4in. The test-cock is made exactly the same as the
x 40 union nipple is silver-soldered into the side. blow-down valve specified for my water-gauges,
and is shown in section. Screw it into the
backhead at I in. from the top, and 1/2 in. to the
right of the centre line. A 1/8in. pipe is connected
to the valve by a union nut and cone, the outer

THE MODEL ENGINEER JANUARY 5, 1950
end being taken to some point where you can No. 50 drill, open out to 5/16 in. depth with 5/32-in.
or No. 21 drill, turn down 5/16 in. length to 7/32 in.
see it easily : say to the underside of the step, diameter, screw 1/8 in. length 7/32 in. X 40, and
part off at 3/8 in. from the end. Drill four No. 55
like an injector overflow. When filling the holes in the top, pepper-box fashion. The ball,
boiler to start from all cold, either pour water in cup and spindle, and spring are fitted, same as I
via the filling-plug, or pump it in with the hand- have described for valves of the usual type, and
pump in the tender, until water runs out of the the assembly is shown in the little illustration.
pipe. Leave the valve open whilst filling, to let The pressure is adjusted by screwing the nipple
air escape from the boiler. up or down, as usual. As only the 7/32-in.
column projects above the firebox casing, the
The steam-gauge fitting is made exactly the appearance of the valve is correct.
same as the blower connection ; but the block
may be round instead of square, and screwed into
the backhead if you prefer it. The pipe is bent

3/16" x 40 FILLING PLUG 5,

5
L.
%i DRII
40.

BALL

c-4RE M'6
3'a"

Lubricator Safety-valve Feed clack

to U-shape ; and the steam gauge, which should Assembly and Erection of Boiler
be 3/4 in. diameter, reading to 120 lb., is attached to Line the inside of the firebox casing with
the union as shown. The feed clack is just
one of my standard clackboxes, screwed into the 1/16in. asbestos millboard. If you damp it,
backhead as shown ;the 1/8in. pipe from this, the stuff can be moulded to the casing without
goes down through the footplate to the under-
side of the drag beam, where it is attached to a breaking ; and a couple of strips of metal about
1/4in. x 26 union screwed through the upper
part of the bracket which holds the feed tubes 3/8 in. wide and 2 in. long, one at each side of the
of the burner in position. The coarser thread lower part of the casing, will keep it in place.
gives quicker attachment and far more lasting They can either be riveted with two 1/16in.
wear than the usual 40, in this case. rivets in each (one at each end) put through the
lot-casing, asbestos, and strip-or screws can
The safety-valves are similar to those I be used, nutted inside. The boiler is just slid
schemed out for a close friend of Inspector into the casing, and secured by a few 1/16in. or
Meticulous, who wanted “ scale ” safety valves 10-B.A. screws put through No. 50 holes in the
edge of the wrapper, into tapped holes in the
backhead flange.

(Right) Details of regulator

on a 2-1/2in. gauge engine. He got the “ scale ” The smokebox saddle may either be a little
appearance, though he didn’t get “ scale ” casting, or built up from 18- or 20-gauge sheet
metal, to sizes given. You can see where to put
valves ! These were large enough to be effective, it, in the general arrangement drawing published
in first instalment ; it is set so that the bottom of
owing to each valve being housed in the block the radius is level with top of frame, and fixed
below the column. In the present case, chuck with three 1/16in. or 10-B.A. countersunk screws
a piece of 3/8in. bronze or gunmetal rod, face the at each side. Drill clearing holes in the bottom
end. centre. and drill down about 1/2 in. depth with of smokebox. for pipes to pass. Place boiler in
No. 44 drill. Turn down 5/32 in. of the end to
7/32 in. diameter and screw 7/32 in. X 40, part position, and set it level ; then drill a No. 48
off 1/4 in. from the shoulder. Reverse in chuck,
open out the hole to 3/16 in. depth with 3/16in. hole at each side of frames. anywhere between
drill and D-bit, or easier still, use a pin-drill ; the wheels, and tap it 3/32 in: or 7 B.A. Remove
tap 7/32 in. X 40, and poke a 3/32-in. parallel boiler, and put a No. 40 drill through the holes in
reamer through the remnants of the small hole
at the bottom. For the nipple, chuck a piece of the wrapper ; then elongate them into little
5/16in. rod ; face, centre, drill to 1/2 in. depth with
slots with a rat-tail tile. Replace boiler, and put
screws in ; the slots will allow for expansion of

19

THE MODEL ENGINEER JANUARY 5, 1950
boiler when hot. To fix the front end down, gauge, or thinner if you can get it. These are
utilise the steam union. Chuck a bit of 5/16in. mounted on two pieces of 1/4in. tube, also as thin
as possible, holes being drilled, or half-round
hexagon brass rod ; face, centre deeply., and drill nicks filed, at the points where the feed-pipe
passes through the burner. Discs of thin brass
down about 1/2 in. depth with No. 30 drill. Turn close the bottoms, and the whole issue is silver-
a bare 1/4 in. length to 1/4 in. diameter, and screw soldered at one heat for each unit. Both units
are silver-soldered to a cross-pipe or drum,
for the union. Part off at 1/2 in. from the end ; made from same stuff as burner tubes, closed

reverse in chuck, turn about 3/16 of the end to a
taper, and tap the hole 5/32 x 40. Screw this
on to the end of the bit of tube projecting up

Steam and exhaust pipes Smokebox saddle

from the steam tee into the smokebox, so that at each end ;a short bit of 3/16in. pipe is silver-
the taper fills the hole, and holds the smokebox soldered into the back of the drum, for connection
to tender by a rubber hose. A bracket I in.
down ; a bit of plumber’s jointing on the threads, long is bent up from 13-gauge sheet metal, and
attached to the drag-beam by two screws, as shown
and around the taper, will keep it steam-and-air- in the illustration ; a piece of 16-gauge metal,
tight. Put some around the blast-pipe as well. I in. long and 5/16 in. wide, holds the feed tubes
Connect up the end of the superheater loop to to the underside of the bracket, and is itself held
the union, and Bob’s your uncle. The front of up by a solitary 3/32-in. or 7-B.A. screw, passing
the smokebox is a casting, complete with door between the feed pipes and entering a tapped hole
and hinges cast on. It is turned to a push fit in in the bracket. Use asbestos string or flock for
the front of the smokebox. The chimney and wicks.
liner are a half-size edition of those specified for
“Doris,” and fixed in the same way. The An oil burner may be fitted if desired ; the
dome casting, after being turned, is attached “ axle-dodger ” type shown on the blueprint
to the top of the filler screw by a 3/32-in. or of my oil burners issued from our offices, could
7-B.A. countersunk screw. The complete assem- be reduced to suit, and would make enough
bly is shown in the illustration. steam to haul a couple of kiddies continuously.
There is no need for separate instructions and
Firing Arrangements drawings for the superstructure, as the running-
The easiest method of firing the boiler is by a boards, cab, and trimmings are all made like
those for “ Doris,” but to half the given sizes.
six-burner “ poison-gas plant,” but if your blast Now all we need, is a suitable tender ; so I will,
and blower are O.K. you’ll take all the poison all being well, dispose of that in a final instalment.
out of the gas ! The burners are six 1-1/4in.
lengths of 3/8in. brass tube, not thicker than 26-

A Lincoln " Double "

(Continued from page 9)

Rodway were given a trip behind “Bantam The multi-gauge locomotive track consists
Cock,” and at the end of his trip Alderman of a 400-ft. oval, comprising two 90-ft. straights
Doughty stated it was one of his greatest thrills. and top and bottom curves of 34 ft. radius.
Construction is of concrete arches resting on
While the locomotives were being prepared footings cast in position. Arches are of 6-ft. span
for passenger-carrying, attention was next and are 16 in. in height. Rails are laid in a trough
‘centred around the race car track, where several cast in the top of the arches, and consist of 9 ft.
lengths of 1-in. x 1/4in. mild-steel bars, held
fast runs were made ; unfortunately the electrical apart by tubular spacers.

timing gear had not been completed, so accurate The race car track is laid out inside the rail
timing was not possible. track and consists of a ring of concrete 3 ft. wide,
42 ft. diameter, and is cast in six sections, all
Among the cars running were Mr. C. Bunn’s correctly reinforced.
I O-C .C . D-type E.R.A., Mr. L. Goodacre’s
2.5-C.C. free-lance and Mr. H. Butler’s 2.5-C.C. The timing-gear is of the electrical contact
D-type E.R.A. type, the contacts being actuated by the centre
tether-arm.
Unfortunately, rain “ stopped play” at tea-
time, but in the meantime, well over 300 passen-
gers had been carried.

20

Tender for the Wee " Dot " like " D o r i s"

b y " L.B.S.C.”

A S full instructions were given for building Our “ approved ” advertisers can supply little
the tender for the 3-1/2in. gauge engine, there castings comprising axlebox, horncheeks, spring
isn’t much to say about the tender for the little
one ; but the latter differs a little, inasmuch as and hangers all cast as a single unti ; and all
there is no coal space, and an extra tank is carried
for methylated spirit. If anybody prefers to they need is a clean-up with a file (a couple of
fit an oil-burner, leave out this tank ; and, all samples received, don’t even need that much,
being well, I will give the drawings and a few being very clean) and the hole drilled for the
notes for a suitable oil-burner of the “ axle- axle. The easiest way for beginners to do this,
is to rivet the casting to the frame, by two 1/16in.
rivets through the ends of the dummy spring,

LM

General arrangement. and frame of tender

dodger ” type. The tank for this will be circular, taking care to locate the axlebox centrally over
and will fit in the space allotted to the “ poison-
gasA”s container. the hole in frame ; then poke the No. 30 drill
will be seen from the accompanying outline
drawing, the tender differs little in personal through the hole in the frame, and carry on nearly,
appearance from “ Doris’s ” tender, but it is but not quite, through the axlebox. An inch
much simpler to build up. The frames can be of 1/16in. by 1/4in. brass angle is riveted to each
made from any bits of 16-gauge metal you have side, as extra support for the soleplate, which is
handy ; brass, steel, or galvanised iron, will do screwed down to it.
equally well. No horn slots are needed, the
axles running through plain drilled holes in the The drag-beam and buffer-beam are made from
frame, into blind holes drilled in the axleboxes. 1/2in. by 3/32in. angle, brass or steel. They
There is no need to spring this little tender when are drilled and slotted on the vertical faces, same
the engine is used on an indoor “ scenic ” railway. as the engine, but the tops are not slotted, merely
cut the corners away as shown, and rivet pieces of
angle flush with the edges of the cut-away part.
You can’t very well braze up this frame assembly,

40

THE MODEL ENGINEER JANUARY 12, 1950
otherwise you won’t be able to get the wheels body can be made from a single strip of 20 - or
22 -gauge brass or copper-hard-rolled brass is
and axles in ; one side of the frame has to be the stuff I use-and it may be soldered direct
to the soleplate, merely putting a little bit of
detachable for this purpose. The frames are angle near each front end, and another little bit
screwed to the bits of angle as shown in the at the back. No need to rivet or screw them ;
illustration. Maybe our advertisers would supply just drop in place, solder over the lot, and don’t
cast beams with lugs instead of angles, to which forget to cover the screw-heads. Cut a division
the frames could be screwed. plate from the same material as the body, and

The wheels and axles are turned, as described
for the bigger engine (beginners can follow the

CAST DUMMY SPRINGS

__.-&__ .-.

Part plan of frames erected

machining instructions given for “ Tich “) and, solder it across the body at 5-1/2 in. from the back
as mentioned above, are put in place when the end ;this should be 1-3/4 in. high, and a nice fit
frames are screwed to the beams. The little between the two sides. The space between this
chassis thus far constituted, shouldn’t rock when plate and the back of the body, forms the water-
placed on the lathe bed or something equally flat tank. Rivet a piece of 1/4in. by 1/16in. angle-
brass along the top, and along each side and
and level ; and-hold your breath-it won’t back, as shown in the section, for attaching the
collapse if you stand on it ! The true test for removable cover-plate. This is made and fitted
as described for the 3-1/2in. engine, and has a filler
a locomotive frame is not to stand on it, but hole with hinged lid as shown.
bash it cornerwise against a concrete post or
something equally solid. This test won’t hurt The spirit tank is made from a piece of sheet
a frame with angle buffer beams, but it will metal, same kind as tender body, 4-1/8 in. long, and
probably make a lovely rhomboid of one with

!r---._ &__/

Buffer and drag beams Wheels and axles

plate beams and thin staying. I’ve seen ‘em! just wide enough to fit between the sides. Bend
If the end wheels touch the flat surface, and the it at right-angles, at 2-1/2 in. from one end ; drill
middle ones don’t, put a drill a shade larger in the hole for the filler-plug bush before soldering
the middle bearing holes. This may upset it in place, then fit the bush and solder that in
Inspector Meticulous, but it won’t affect the too. A 2-in. length of 1/4in. thin brass or copper
running of the tender one iota, and that is all tube, is soldered into a hole drilled in the sole-
that matters. plate, 3/8 in. off centre line, and 1-3/8 in. from front
edge of soleplate ; bevel off the bottom as shown.
Tender Body Level with this, and 3/8 in. off the opposite side
The soleplate is made from 18-gauge brass or of centre line, fit the fuel valve shown in the
cross-section of the tank. This is merely a long-
copper, and is 8-15/16 in. long by 3-1/2 in. wide. It stemmed edition of an ordinary screw-down
is attached to the chassis by 3/32-in. or 7-B.A. valve, with a valve pin or spindle 2-1/2in. long,
brass screws through the tops of beams, and side made from rustless steel or bronze rod 5/32 in.
angles, the screws being nutted underneath, as diameter. The upper end passes through a
usual. There is no valance on the L.M.S. gland, soldered into the top of the tank. If
tenders of this type. The sides and back of the
41

THE MODEL ENGINEER JANUARY 12, 1950

beginners drill the hole in the tank top first, with
a 3/16in. drill, then carry on through the soleplate,
using the hole in the top as guide, the holes will
be in line. Open out the top hole to 1/4 in.

clearing size ; 7 mm. or 17/64 in. will do, and

turn the spigot on the under-side of the gland
to suit. Assemble your valve, poke it through
the hole in the top, wangle the 3/16in. spigot of the
valve itself, through the hole in the soleplate,
press the gland body down into the hole in the
top, and solder around both. The sump is a
little tank bent up from a piece of sheet brass
1-1/4in. wide, leaving a lug or flange at each end
for attachment to under-side of soleplate by two
screws, as shown in the longitudinal section of
the tender body. The sides are cut from the
same kind of metal, and soldered in ; a short
bit of 3/16in. thin tube is soldered into the front,
right at the bottom. When the engine is coupled
to the tender, a piece of rubber tube is slipped
over this, the other end being attached to the
similar bit of pipe on the little cross-drum
connecting the burner feed-pipes. Thus the
spirit will stand at the same level in the burner

tubes, as it does in the sump ; and the little drum

will ensure that none of the wicks are starved
of fuel. In days gone by, when I had more
energy, and could do a little to help friends out
of trouble. I fitted several 2-1/2in. gauge engines
with this type of feed and burners. The original
burners were made entirely of thick copper tube,
with feed-tubes far too small ; the consequence
was, that when they got hot, the spirit boiled,
vaporised, and blew the contents of the feed
tubes either back into the tank, or out of the sump,
if they had one. The flames then died down
until the tubes cooled a little ; then back came
the spirit, up went the flames, the tubes heated
up again, and the whole process was repeated
I tried to explain the cause of the trouble, to the
designer, in a friendly sort of way, but he would
not take the slightest notice. Such is the way

of the world !

Tender Hand-pump
The tender hand-pump is made as described

for “ Doris ” and other engines in this series of
notes, but is naturally smaller. There is, of
course, no need to keep to the exact type shown ;
one of our advertisers, Messrs. A. J. Reeves & Co.,
supply little castings embodying the base, barrel,
and anchor lug on top. All this casting needs,
is drilling and reaming for the ram, and drilling
for the holding-down screws and the anchor-link
pin. A cast valve-box is also supplied, with a
projection on the side for turning and pressing
into the barrel. The valve-box itself is machined
up exactly the same as one made from rod, and
assembled exactly the same as one with a bent-up
stand, and barrel made from tube.

If the built-up job is preferred, the whole bag
of tricks is shown in the accompanying illustra-
tion. The stand is bent up from a piece of
3/4in. by 3/32-in. brass or copper, with a 7/16in.
hole drilled through both sides at 9/16 in. from
the bottom. The barrel is a piece of 7/16in.
brass treblet tube 1-1/2 in. long ; if the inside
isn’t perfectly smooth, it can be made so in a
very short time, by treatment on an improvised
lap. Wrap a few turns of fine e m e r y - c l o t h

THE MODEL ENGINEER JANUARY 12, 1950

around a wooden meat skewer (if such things used similar pumps for test pressures of 350 lb.
haven’t become extinct-they are hardly needed Buffers, couplings, steps, and any other trim-
for the present size of the meat ration !) or a mings can be “ added to taste ” as Mrs. Beeton
pencil would do. The roll should be a loose
fit in the tube ; grip it in the chuck, run the would remark ; and same applies to the engine,
lathe as fast as possible, and run the tube up and
down the improvised lap for half-a-minute or so. so I guess that no further space need be wasted
on constructional notes; Instructions for the
The result will be alternative oil-burner will appear, by kind per-
mission o f o u r
asmooth and friend the K.B.P..
true pump barrel. as soon as I can
The ram need not make the neces-
be turned at all, sary drawing.
if an easy sliding The description of
fit in the tube ; the “ wee Dot like
all it needs is a Doris ” has been
packing groove. very much con-
Slot the end for densed, as there
a 1/4in. lever. is hardly need to
The valve-box go into full detail,
is machined up when I have al-
from a 1-in. ready fully dealt
length of 5/16in. with the 3-1/2in.
bronze or gun- gauge engine ; but
metal rod-brass if any beginner is
will do at a pinch at all hazy about
-the sizes being how to machine
given in the draw- and fit the various
minget,hod,anthde the components, he
same Tender hand pump has only to look
as described for up the equivalent
the larger pumps, part of “ Tich.”
and ordinary ec- being very fully and completTehlya tdeetanigleidn eouits,
centric-driven pumps. The balls are 5/32-in. dia-
meter, rustless steel or bronze, the delivery especially for beginners’ benefit ; but-don’t
seatings being D-bitted 3/16in. and reamed 1/8 in. laugh too much !-experienced builders of many
and the suction seating formed on the bottom cap. years’ standing have taken a liking to the tiny
The plug for connecting to barrel, is screwed into engine, and many of them are building one to
a tapped hole in the side of the valve-box (3/16 in. keep her more elaborate and larger sisters
by 40) and the spigot pressed into the barrel. company. One advertiser alone, has, at time
All joints may be soft-soldered, as there is no heat of writing, sold over four hundred sets, and orders
to withstand, and the solder is only needed to are still coming in !
stop up any interstices. It is also quite strong
enough to secure the barrel firmly to the stand. Epilogue

The whole assembly is shown in the section, and Maybe I might do worse than conclude the
needs no further explanation. tale with a hint or two on operation. Oil all the
The complete pump is installed in the water- moving parts with any good motor or machine
tank, with the handle exactly under the centre oil, and fill the lubricator about 3/4 full with thick
of the filler hole, when the lever is vertical. Fix black cylinder oil of “ superheater ” grade, such
it down with four 6-B.A. screws through lugs and as Cyltal 80s, Vacuum 600W, or similar grade.
soleplate, nutted underneath. An elbow fitting, This is essential to protect the valves, faces,
very similar to the one specified for the super- and bores from the effect of really hot steam.
heater, but having the end formed like a union Fill the boiler with hot water until it runs out
screw, goes through a hole in the soleplate, a of the test-cock pipe ; hot water saves spirit,
little ahead of the valve-box. This is held in and gets up steam more quickly. Shut the fuel
position by a lock-nut on the union screw, which valve, fill spirit tank about 3/4 full of methylated
should be made about 5/16 in. long for the purpose. spirit (what our old friend Bro. “ Iron-wire ”
The union is connected to the union on the Alexander, one of the pioneers, used to call
pump, by a swan-neck of 1/8in. tube, with nuts “ spirits of wine “) screw the filler-cap down
and cones on each end, as shown in the section tightly, and open the valve. Spirit will flow into
of the tender body. A 1/8in. pipe, with a couple the sump until it fills the burner tubes and covers
of coils in it to provide the necessary flexibility the end of the air-pipe, when the flow will cease,
between engine and tender, is connected to the only restarting when the pipe is uncovered, as
elbow union, and terminates under the front the spirit is consumed by the burners.
beam in a 1/4in. by 26 union nut and cone, for If you have an auxiliary blower, either fan,
attachment to the union on the engine. The tyre-pump, or any other kind, use it exactly
pump is operated by the simple extension the same as for a coal-fired engine ; an induced
h ndle shown, worked through the filler hole ; rush of air past the burners, not only gets up
steam in double-quick time, but “ takes the poison’
and the resistance at the end of a 4-1/2in.
extension handle, is practically negligible even out of the gas” by eliminating the emission of
with 80 lb. pressure in the boiler. I have (Continued on page 48)

43

THE MODEL ENGINEER JANUARY 12, 1950
can be machined in the same way as the other placed opposite the centre of the wheel and the
vee-grooves in the block. It will be clear that,. handle is raised with the right hand until light
when the knurled finger-nut is tightened, the contact is established ; the left hand, meanwhile,
central bolt-will be drawn inwards, thus securely holds the. vee-block firmly down on the guide
clamping the screwdriver blade between the pad- rail. Grinding should be continued for a few
piece and the vee-groove formed in the end of the seconds at a time only, otherwise there is a danger
of drawing the temper of the blade. Grind first
block ; furthermore, the pad-piece itself can be one side of the blade and then the other to keep
the tip symmetrical. Examine the faces from
adjusted to accommodate blades of various time to time, and try the blade in a standard
diameters. screw slot, or one of a width commonly used,
until it is found that a good fit in the screw head
Fig. 9. A chuck used to mount a small blade in the has been obtained. If the work has been properly
vee-block carried out, the hollow-ground faces should
appear as smooth continuous curves quite free
Holders for Small Blades from ridges or other blemishes.
Some small screwdrivers are furnished with
When grinding the blade with flat faces by
detachable blades which are too short to provide using the side of the wheel, the blade is pressed
the necessary overhang when secured in the lightly against the wheel for a few seconds and,
vee-block. In this case, as represented in Fig. 9, at the same time, the handle is alternately raised
the blade is mounted in a holder or chuck which, and lowered to keep the work moving. This
in turn, is clamped in the vee-block ; but a method of grinding has the disadvantage that
carrier such as th e “ Eclipse ” pin vice will be the scratch lines formed by the wheel run across
found less cumbersome for mounting blades the blade and in the direction in which the blade
up to 3/16 in. in diameter.
is stressed when i n use ; this renders a hardened
An alternative method of holding small round
blades is to use an appliance similar to that tip more prone to fracture than when the grinding
illustrated in Fig. IO. This holder can be made lines lie in the direction of the long axis of the
from a length of, say, 5/16in. diameter round mild- blade.
steel, and the end of the shank is knurled to
afford a better finger-hold. The rod is drilled L1_’\._-=_‘,_.‘-.J,
axially to fit the screwdriver blade, and a piece
of steel to carry a binding-screw is silver-soldered Fig. IO. A holder for small blades
to the front end. Whenever carriers, of the forms Apart from grinding the sides of the blade,
described, are used for holding small blades, it is the front face, as the result of wear, may need
important that the blade should overhang the truing. This can be carried out accurately by
holder for as short a distance as possible in order withdrawing the blade in the vee-block so that the
to maintain rigidity and avoid springing when the front edge comes into contact with the wheel
tip is being ground. and at right-angles to it. To avoid a dig-in,
The Grinding Operation however, it is essential that the blade should be
supported close to its tip against the front edge
With regard to the actual grinding operation, of the table, and, at the same time the screwdriver
when hollow-grinding on the periphery of the handle must be held firmly.
wheel is carried out, the screwdriver blade is

“ L.B.S.C."

(Continued from page 43)

unburnt spirit vapour, which is the stuff that kiddy car, or whatever you want the “ wee Dot ”
makes your eyes smart . If you haven’t a blower, to pull, and she will oblige, without hesitation.
take off the front of the smokebox until there is A few strokes of the hand pump every few min-
enough steam to work the engine’s own blower ; utes, will maintain water level. Beginners who
then open the valve, and replace the front. have had no experience of loose eccentric valve-
gear, should remember that to reverse the engine,
Warning : keep the blower on a little, all the it is necessary to move her half-a-turn in the
required direction. Once set, she will continue
time the engine is standing, and always open it to run that way, until reversed by hand again.
The lubricator valve should be opened from
before shutting the regulator ; if you don’t, half to three-quarters of a turn ; an oily ring
at the chimney top is a sure sign that all is
flames will come out from under the firebox
casing. When there is abou t 50 lb. on the well down below. With that, I’ll leave you to i!t
gauge, give her a ru n “ light,” to warm up.
Steam will work up to blowing-off point whilst
doing this ;then couple up your twenty coaches,
48

A Coal-Fired Version of the " Wee Dot

JU D G I N G from correspondence, the wee Dot steam. She would haul my weight continuously ;
had a favourable reception, more locomotive but the fire needed careful attention, more than
builders taking it up than I should have antici- it would be likely to get on the usual small
pated ; but it looks as though some other good railway.
folk beside your humble servant, are not very
keen on “ poison gas plants,” and quite a number Anyway, I thought things over, and came to the
of requests have come to hand for a drawing and conclusion that the best way out of the trouble
a few notes for a coal-fired boiler. This is where would be to follow the good example of the
a little difficulty arises ; I can design the boiler C.M.E. of British Railways, and go in for a wide
all right, and followers of these notes should firebox ; so I put a sheet of drawing paper on the
have no difficulty in building it, but what about board, and made a carbon tracing of the front end
of Dot, leaving out the trailing wheels, cab,

Coal-fired version of Gauge “ I " “ Dot.” (A future B.R. standard

firing it ? There is only a matter of 1-5/16 in. and boiler. Then I just indulged in one of my
between frames ; by the time you have allowed daydreams, which need no assistance from text-
for the thickness of the copper, and say a 1/8 in. book, slide-rule, figures, formulae or anything
water space, we are down to a grate only 13/16 in. else of a like nature ; although a cup of the
wide, if the normal type of firebox is used. There enginemen’s best friend is a very great help.
would be no difficulty in firing this with charcoal Old readers of this journal may recall that by aid
only, but you’d be in the same boat with the of a cup of tea and an aspirin, I designed the
firemen on the spam cans, never able to put the 4-12-2 “ Caterpillar ” goods engine, still going
shovel down. Best quality Welsh coal would strong after some 24 years’ service, without
burn all right, but where are you going to get trouble of any kind. Well, my daydream
any? The last lot of Welsh nuts delivered for materialised, as usual ; “ out of the mist ” arose
our domestic boiler last year, very nearly sent me the figure of Diana, and I added the necessary
“ nuts ” in another sense of the term. Many parts to the carbon tracing, with the result that
years ago I built a gauge “ I ” Hughes type you see in the accompanying illustration. Don’t
L.M.S. 4-6-4 tank engine for an old friend, who be surprised if, in due course, a similar type of
wanted it coal-fired, and I got over the very locomotive in full size, makes an appearance on
narrow grate difficulty by splaying out the side British Railways ; not, of course, with a simple
sheets of the firebox, and riveting them direct loose eccentric valve-gear, but with the usual
to the wrapper sheet, without using a foundation- Walschaerts, or maybe a unit-construction Baker
ring. This permitted a grate just a shade over gear.
I in. wide, though the actual firebox was narrower
above the grate. With a good hearty blast, the This Comparison isn’t Odious !
fire burnt well-the coal was ever so much better
in those days-and the engine made plenty of The coupled wheelbase of Dot is unequally
354 divided, and fairly long, like most engines of the

Dot Like Dosri ” by " L.B.S.C.”

4-6-0 type ; and visualising her as a 4-6-2 with is all we builders need worry about !
the same coupled wheel spacing, she looked like
a Jerry poodle. I therefore set the trailing coupled In place of the weeny grate area of the 4-6-0,
wheels a little more forward, so that between we have a grate approximately 2-5/8 in. long and
leading and driving, axles driving and trailing, the 2-1/4 in. wide, not much smaller than Ayesha’s ;
and with a combustion-chamber in the barrel,
spacing became equal ; this shortens the engine there won’t be any difficulty in keeping steam up.
In fact, if you like, you can enlarge the cylinders
without altering the working parts in the least. to 5/8 in. bore, or even larger than that, if the
To enable a 4-6-2 to get around the same curves
as a 4-6-0, the pony truck needs plenty of side castings will stand it ; and the engine won’t over-
movement, so I abolished the trailing cradle
altogether, and substituted a simpler arrangement. exert herself with a load of, say, two hefty adults
or four children. Slightly different from the

c------__ 39fi’L_ ;_- ~- -. i

tandard type ?) Part cross section

The king pin of the pony truck is attached to the gauge “ 1 "toy locomotives that came over from
bottom of the ashpan by a bracket, and the top Nuremberg in the days before the Kaiser’s
of it projects above the bracket and fits into a hole war !
in the cross member or brace at the end of the If you take a look at the back view, which is
mainframes. : The cross stay at the rear of partly cross-section, you will see that the boiler
the pony truck is arranged to connect up to the backhead, and the cab front., are what will be
drawbar on the tender, so that the pull is taken standard B.R. patterns, so builders of Diana will
through the pony truck frames ; and this has have a B.R. type engine on the road, long before
the added advantage that the pull is almost central the first big sister leaves the shops. We could
with the rails, whereas with the usual arrangement put in the new regulator as well, with its side
of drawbar, pulling from the drag-beam, the pull handle, and rod outside the boiler, but it would
is right over to one side, when the engine is on a be rather too fiddling on such a small engine.
fairly sharp curve. This is due to the overhang A coal-fired boiler should have a regular feed,
of a long engine ; and- with a heavy load, tends and not rely on the hand pump in the tender ;
to cause derailment of the tender. There is no so I will give details of a suitable pump, all being
drag-beam at all ; merely a sill under the cab well, along with the drawing of the boiler.
floor, the cab being attached to the boiler, which Alternatively, one of my weeny injectors, with
will be standard B.R. practice. Another ad- specially small cones, could be fitted alongside
vantage is that when the grate-dumping pin is the firebox (another B.R. standard-to-be).
pulled out, the trailing truck comes away with Forgive my smiling as I write that ; a very short
the ashpan, leaving the firebox perfectly un- w“"hiIle” agliov,ethpeasidseena goefr-fheeaduilningga coal-fired gauge
obstructed. Pulling through the pony truck is engine with an
“ all wrong,” athcicsorsdiziengof tlooctohmeotbivoeo,ka, nbdutthaitt injector, would have been ridiculed as the product
works O.K. on of a crazy brain. We ‘live and learn !

355

THE MODEL ENGINEER M A R C H 16, 1950

Variation for “ Atlantic ” Type (or rather its share of the weight) of the trailing
Anybody whose curves are too sharp to admit end via a flat spring attached to the underside of
the ashpan. This will be shown in the detail
of a “ Pacific ” type engine running around them, drawing of that component, along with the
can shorten this locomotive into an “Atlantic” description of the boiler. The stay is just a
without interfering in the slightest with the strip of 16-gauge steel, 3/8 in. wide, bent up at an
working parts. Simply cut the frames off at angle each side, to fit between the frames of the
1-1/4 in. behind the driving axle, and shape them, pony truck ; see plan view. If you hold the
as shown by dotted lines, and fit the cross stay, strip of metal against the bottom of the frames,
also the pony truck, exactly as described below at the correct location, and scratch a line across
for Diana.You then have a 4-4-2 chassis, with a the ends, holding the scriber point against the
fixed wheelbase of only 2-5/8 in., and that should inside of the pony frame, it will show exactly
very nearly run around the edge of a dinner- where to make the bends. Alternatively, the
plate. The firebox will be exactly the same size strip need not be bent at all ; personally, I
as for the 4-6-2, but the combustion-chamber should cut the ends off to the same angle as
will be omitted, the tubes and superheater flue frames, jam in position, and give each side a spot
running from the smokebox tubeplate, through of my old friend Sifbronze. Brazing or silver-
the shortened barrel, to the front plate of the soldering would do equally well. SDeot nt’ht efisxtaiyt
firebox. The cab will be exactly as shown, and a level with bottom edge of frames.
similar tender can be used. permanently until the wheels and axle have been
fitted ; see below.
4-6-0- to 4-6-2 The combined stay and drag-bar which
Here are a few details for altering Dot to Diana. connects the back ends of the pony frames,
is made from a piece of 16-gauge steel 3/4 in. wide,
Anybody who has already built the 4-6-0 and and approximately 2-7/8 in. long. First bend it to
wants to convert it to 4-6-2, may, if they so the shape of an angle with a slight radius instead
desire, keep to the original wheelbase, and merely of a sharp bend (see elevation view), an easy job
add the trailing truck, and lengthen the boiler to in the bench vice. Tip for beginners : set it in
suit the 4-6-0 coupled wheelbase. Those who the bench vice with half the width projecting ;
are starting from scratch, and others who don’t hold a bit of iron bar against the piece standing
object to a little extra trouble, can finish off the up above the vice jaws, and hit the bar with a
rear end of the frame assembly as shown in the fairly heavy hammer a few times. That will give
accompanying illustrations. Cut the frames off it the K.O. in a matter of seconds, and the piece
short, 1-1/4 in. behind the centre-line of the trailing won’t be marked, as the bit of bar distributes the
axlebox opening, and snip the corners diagonally force of the blow, the full length of the metal. I
as shown. Cut a piece of 1/2in. by 1/4in. brass did most of my bending that way before I had
bar to a little over 1-5/16&in. in length, then square the " Diacro ” bender. Cut one of the angles to
off both ends in the chuck, exactly to that the shape shown, leaving a tag at each end a full
measurement. Drill three No. 41 holes at the 1/4 in. long, which is bent backward at right-angles
bottom of the frame, in the places shown, and (see plan view) and attached to the end of the
fix the cross member by aid of 3/32-in. or 7-B.A. pony frame by a couple of 1/16in. rivets. The
countersunk screws. Exactly in the middle, distance between frames should be 2-5/16in.
on the underside, drill a No. 30 hole halfway Note--don’t fix either stay permanently until
through ;that is, to a depth of 1/4 in. ; see that the wheels and axle are ready for erection, or
the drill goes in square with the bottom. This you won’t get them in. The wheels and axle are
is to accommodate the extension of the king-pin, made up similarly to the tender wheels and axles.
and allows the pull to be transmitted through the wheels being 1-1/4:in. diameter on tread, with
the pony truck instead of the boiler. flanges 3/32 in. deep, the hole in the middle being
reamed 5/32 in. The axles are turned from
Pony Truck 3/16 in. round steel held in the three-jaw, wheel
It is quite possible that castings will be supplied seat and journal being turned at the same setting.
The cast dummy springs and axleboxes may be
for this, with dummy axleboxes and springs exactly the same as described for Dot’s tender,
cast on. A separate casting, one right hand and and fitted in the same way, the holes for the
one left, would be needed for each side ; alter- journal being drilled through the hole in the
natively, the whole pony truck, including pivot pony frames, after the castings have been attached
block, cross stay and drag-bar, could be in one to them. The whole bag of tricks can then be
piece; and have separate- dummy springs and assembled as shown in the plan view, and a
axleboxes attached. For built-up construction, No. 40 hole drilled in the drag-bar, to take the
two pieces of 16-gauge steel will be needed, drawbar pin.
same stuff as used for main frames, each 3-7/8 in.
long and 7/8 in. wide. Cut these out together, Cab
same as main frames ; drill the holes for screws Anybody who completes the frame alterations,
and axle, then bend to shape shown in the
illustration. The narrow ends are screwed to a and makes up the pony truck, and is stuck for a
1/2 in. length of 1/4 in. square brass rod, faced off job whilst I make the drawing of the boiler. can
cut out the cab, The size and shape of the front,
truly at each end ; a simple chuck job. I have or weatherboard, is shown in the part cross-
section of the trailing end of the engine. Don’t
shown two screws, for neatness sake, but a single cut the boiler opening until you have made the
large screw, say 1/8 in. or 5 B.A., would do equally boiler ; it is easy enough t o fit the cab to the
well at each end. Drill a No. 30 hole in the
middle for the king-pin.

A cross stay is needed, not so much to stiffen
the little triangular frame, but to take the weight

356

THE MODEL ENGINEER MARCH 16, 1950

boiler, but not so easy to fit the boiler to the cab ! is on ; and I hope to describe t h e boiler in the

The sides are shown with the “ tumble-home ” concluding instalment about Diana.
that British Railways are adopting-similar to Generalities
the “ Schools ” class on the old Southern-
but the front is flat “ for the sake of simplicity,” The letters about cylinder steam passages have,
with apologies to a famous catalogue. The up to time of writing, all been very interesting;
window openings in the cab front, may also be and your humble servant is gratified to know
left until the opening for the firebox wrapper is
cut out. The inner edges follow the same Pony truck
contour. that the sizes given in my instructions are
generally approved. The simple explanation
The exact length of metal for the sides and of the whole business is that I reckon out the
top, which are all in one piece, can easily be size of my steam ways, to pass “ without let or
obtained by running a bit of soft wire around the hindrance,” the amount of steam needed to do
edge of the cab front, and straightening it out. the job. Just that and no more. As all my
When making a cab of this kind, I should make engines do the maximum amount of work, on
a paper pattern first-the dressmaker of child- the minimum amount of steam, they don’t
hood days taught better than she knew-as a
dozen pieces of paper spoilt, wouldn’t “ break require huge passages ; but they do require big
the bank,” whereas you might make an apple-
pie of your last bit of metal. Incidentally? 22- ports, so as to get the largest possible opening in
gauge sheet brass, or steel, would be just right ; the shortest space of time, and enable the small
the same thickness used for the cabs of the Bulleid
engines on the Southern, rather different to the
3/16in. stee! plates used for the cabs of the old

Brighton engines ! The strip of metal should

be 2-5/8 in. wide, to allow for the extended roof.
The opening for the “ sunshine roof,” or sliding
part, is 2-1/2in. wide, and 1-5/8 in. long, a runner
being fixed to each side, in which the removable
part slides. This can be taken right off when
running, and renders the “ handles ” and the
firehole quite accessible. The lower part of the
cab is 2 in. wide.

The sides of the cab are 2-1/4 in. high, half
vertical, half canted, to match the front. The
windows are very large-one of the desirable
features stressed for the new cab. In this little
engine they can be made 15/16 in. high, and 13/16 in.
wide, and “ glazed ” with a strip of mica attached

Rear end of main frames Pony wheel and axle

to the inside, similar to the arrangement I have amount of steam to get busy on the piston-head
described for larger engines. The sill under the at the instant the crank has passed the centre.
rear edge of the cab is made exactly the same It may not be “ text-book,” but I submit it is
as the drag-beam of Dot, except that no draw bar “ common-sense,” and it certainly does the
slot is needed, the draw bar being attached to doings, which is all that matters.
the pony truck, as previously mentioned. The
cab cannot, of course, be erected until the boiler My big ports have been derided, time and
(Continued on page 367)
357

THE MODEL ENGINEER MARCH 16, 1950
movement to some extent, there will be scraping that there is no room to accommodate the two
trouble, even when the brakes are “ off.” bolt heads where the holes break through, very
near the foot of the No. 5 stretcher, then counter-
Next, see that the shoes are quite free on the sink these two holes in the cylinder cover only,
hangers. The extent of the freedom required and fit short screws which will not need to go
will be seen when the hanger and shoe are in through the diaphragm at all. The other four
position, when it will also be convenient to see holes should be carried through, just as shown on
that the hanger has sufficient freedom to allow a the drawing, and as the working pressure on the
good “ off” position without moving back far cylinder will always be in an upward direction,
enough to touch the adjoining wheel. the remaining four bolts will be quite sufficient
to hold the cylinder firmly in all circumstances.
The brake shoes are shown with a stop peg You can use the cylinder cover as a drill jig,
which can be filed down to allow the right tilt remembering to leave out the drilling of the two
for the shoe, and to prevent it swinging so far holes mentioned.
down that its top edge trails the wheel tyre when
the brakes are in the free position. It may not The brake cylinder plunger is shown with a
be necessary to fit the pegs at all, and I suggest 3/16 in. diameter stem, and as this passes through a
you try all the parts in place, and carry out the 1/4 in. hole in the trunk member of the cylinder
tests suggested before resorting to the peg fitting. assembly, and has only to provide free air
The prototype has similar stops in the shoes, so clearance past the rod, you might increase the
there will be no need for red faces if your friends rod size to 7/32 in., or a little over. This would
catch you at the job of fitting pegs. have the effect of giving the plate part of the
piston assembly a slightly improved seating,.
The brake cylinder position may necessitate
the removal of the heads of one or two of the Both the sets of brake gear on the two engines
rivets on the forward edge of the rear diaphragm back here, are finished and work according to
-just chip off the heads affected, with a small plan, and as at the: time of going to press I can
flat chisel, leaving the rest of the rivet in place. find no other alterations or improvements to offer,
we will leave it at that.
The drawing also shows the hexagon-headed
set-bolts passing through both the diaphragm (To be continued)
plate the and cylinder cover, and if you find

“ L.B.S.C."

(Continued from page 357)

time again, on the grounds that with the specified you will, of course, agree. Supposing that a t
valves and setting, they never open fully on the the instant the piston arrived at the firing point,
steam side. They are not intended to-but what the full charge, ready compressed and ready for
the critics overlook, is that they open fully on the the ignition spark, could be introduced into the
exhaust side. What that means, is obvious to cylinder, and fired. The engine would go far
anybody who knows anything at all about full- better, and give far greater power, as it would have
size locomotive practice, and-very important no compression strokes to overcome ; in fact,
this-is free from prejudice. In some quarters, two cylinders would do more work than four, as
anything that “ L.B.S.C.” writes, says, or does, the engine would become a glorified non-com-
must be all wrong, because I don’t go by “ the pressing “ two-stroke.” Something like that
book,” preferring the results of my own ex- happens at each end of the cylinder at every turn
perimenting with locomotives on the track. An of the wheels on my little locomotives, which
eminent “ full-size ” locomotive superintendent
told me, in my own workshop, that more useful explains one reason why they do the job ; they
data could be obtained by sending a locomotive
out on the road, with a driver and fireman who don’t “ fire ” naturally, but the charge of steam,
knew their business, plus an inspector to take introduced’at the right time, and hot enough to
the notes, than by any other means ; and he obviate any chance of condensation, does its
gave me, in confidence, a few illustrations which, work by expansion. Ridiculously simple, isn’t
if I disclosed them, would properly “put the it ? In the valve-gear of Lady Vera, there was a
“ little bit of something that the others haven’t
cat among the pigeons.” ‘Nuff sed !
got ” !
The idea of compressing steam at the end of
the stroke, to steam-chest pressure, before the I note that the question of compound engines
valve opens the port to steam, is an out-and-out has been mooted once more. My three-cylinder
fallacy. I’m not trying to be dogmatic ; merely Webb compound Jeanie Deans is anxious to
meet, and have a dust-up with any freak com-
stating facts. Proof? Sure ! Stick the starting pound of her own size, with any number of
cylinders, who fancies its chances at running
handle in your car, and turn it, especially if it 2 miles on one firing with an inaudible blast.
happens to be a cold morning. Wants a bit of Finally, an eight-impulse engine, such as Tugboat
turning, against the compressions, doesn’t it ? Annie, is far less prone to slipping than any four-
Well now, supposing that there weren’t any cylinder engine with opposed cranks ; the reason
compressions at all, the handle would turn easily ; being, that the turning movement is far more even.

367

" Diana "- A Coal-Fired Version of

ALTHOUGH this boiler was schemed out by aid of the usual pan of coke or breeze. Inci- I
especially for those builders who wanted a dentally, a beginner recently wrote me and asked
coal-fired edition of the “wee Dot like Doris,” what size blowlamp would I recommend for
it can be adapted practically to any type of brazing up a 3-1/2in. gauge Pacific boiler without
Gauge “ I "engine with a wide firebox ; and so the need of a pan of coke, as he wanted to do the
should supply the answer to those correspondents job indoors, and was afraid of the effects of the
who have written to me asking for details of a fumes from burning coke. Well, I just told him
coal-fired boiler suitable for Gauge “ I " Pacifics that he would need a lamp giving a flame big

Longitudinal section and cross section at firebox of boiler for ” Diana ”

of L.M.S. and L.N.E.R. outline. Simply put enough to envelop the whole boiler ; I didn’t
t h e firebox, combustion chamber, and tubes
into the shell of any particular type you fancy; think such a lamp was made commercially, but
if it were, personally, I shouldn’t care to operate
you’ll get the steam all right ! Small variations such a fearsome weapon indoors. I still recollect
when the vaporiser of a five-pint surplus lamp
in size, won’t have any adverse effect, as long burst in the bathroom at my o!d home at Norbury,
as the general arrangement of the whole doings is when I was doing a job indoors-against my will-
as shown in the illustrations. The firebox and

BLOWE
UNION

Smokebox tubeplate t- APPROX 1-3/ 4

other internals will fit inside a round-topped (FIT TO COMBUSTIO--NI
wrapper sheet, and it doesn’t matter a bean if CHAMBER)
the boiler barrel is parallel, or of larger diameter.
The construction is pretty much the same as Combustion chamber tubeplate
described for larger engines, such as Hielan’ Lassie
but the job is naturally much easier to heat up, because it was raining cats and dogs outside, and
and keep hot ;a 2-1/2pint blowlamp, or equivalent the boiler was urgently needed. It was the nearest
gas blowpipe, should do the needful quite easily, I ever got to a hospital job during my whole
514 experience of locomotive work, both big and
little. May I remind beginners that the best
time and place to do your boiler-brazing, is in
the back garden, on a fine evening, just as dusk
is falling. You don’t become three-parts roasted,
nor half gassed with coke fumes, and you can see
the brazing material running, ever so much

the “Wee Dot Like Doris” by “ L.B.S.C.”

easier than in bright daylight. That was my 1/4n. steel or iron plate, less 1/16 in. all around
usual practice in days gone by, before I went the inside measurement of backhead and throat-
plate (measure from the cross section at fireboxj,
in for oxy-acetylene equipment ; and experience then flange the plates over it, as described for
previous engines. Cut a. hole in the throatplate
teaches. Also, never do any brazing, silver-
soldering, or even soft-soldering, in your 2-1/8in. full diameter ; rivet the throatplate in
workshop, or you’ll have all bright parts of
tools and machinery go as rusty as an old horse- place with a few 1/16in. copper rivets, fit a “ piston-
shoe in no time. ring ” in the hole (strip of copper sheet about

PLAIN BUSH.

How to Build Up the Outer Shell 1/4in. wide, bent into a ring) and fit the barrel
Now let’s make a brief run through the con- over the ring. Then go ahead and braze up,
struction. Soft copper sheet of 18-gauge will as described for Doris. Stand the lot on end in
be just right for the barrel and firebox wrapper. the coke, barrel pointing to the stars, smear
There isn’t the slightest need to bother about some wet flux around barrel and throatplate
marking out the sheet for the taper barrel, by joints, pile up coke or breeze all around, almost
the geometric methods set out in the text-book ; to level of joint, heat to red, concentrate lamp
life’s too short ! Just cut a piece of sheet copper flame on one corner, then when bright red, apply
about 8-1/2 in. long, 7-1/4 in. wide at one end, and 6-1/2 in. the easy-running brazing strip and work your
at the other ;that is, tapering 3/8 in. each side. way, inch by inch, steadily around the whole
Eend this around anything handy, of suitable issue, feeding in the strip to form a neat fillet
size, letting the edges overlap until the smaller all around the barrel, and filling up the groove
end is 2 in. across, and the larger end 2-1/4 in. ; between throatplate and wrapper. There
put a few 1/16in. copper rivets in the seam, to shouldn’t be the slightest difficulty in this small
make it “ stay put ” whilst being brazed. File boiler, in getting the brazing material to flow
off each end square with the seamed side, so almost like water, and run perfectly without
that when erected, the seam will be underneath, forming lumps of “ almond rock ” in the joints.
level, and parallel with top of frame, whilst the Any beginner who has only a one-pint lamp or a
top of the barrel slopes 1/4 in. from smokebox end small gas blowpipe, could use a coarse grade of
to firebox end. A try-square applied to the silver-solder, such as Johnson-Matthey’s B6
bottom, will show at a glance if the ends are alloy. This costs more than easy-running strip,
square with the bottom. but is not too expensive. Warning to beginners :
The wrapper sheet of the firebox can also be When I say small gas blowpipe, I’m not referring
cut from 18-gauge copper, and shouldn’t be to the tiny things sold for half-a-crown or there-
any trouble to bend over a bit of rod projecting abouts, under fancy names. They are all right
from the side of the jaws of the bench vice. for little things like fittings, union cones and
Start with a piece 8-1/2 in. by 3-3/8 in., bend to shape, suchlike, but utterly useless for boiler-work.
then trim up each end to form the slopes of When the above job is done, lay the shell on its
backhead and throatplate. One former will back in the pan, and do the longitudinal seam,
do for both of these ; make it from a bit of being careful to cover the rivet heads ; then

515

THE MODEL ENGINEER APRIL 13, 1950
pickle, wash off in running water, and clean up edition of the one on the combustion-chamber,
with a handful of steel wool. Clean copper is but as it fits inside the end of the barrel, turn the
outside of the flange to a tight fit. The inside
much nicer to handle ! of the barrel should be filed a wee bit, to bring it
parallel ; the tubeplate only goes in for half the
Firebox and Combustion-Chamber width of the flange, as the projecting part is used
Firebox and combustion-chamber are cut for mounting the smokebox (see illustration)
The four tubes are 3/8in. diameter, and 5-3/4 in.
from a single sheet of 18-gauge copper, roughly long. If you are fairly experienced at boiler-
7 in. by 6 in. The diagram shows how to cut it. smithing, use 24-gauge tubes, but if a raw
First bend the whole lot into the shape shown recruit, use 22-gauge ; you won’t be so liable
in the cross section ; then carry on with the to burn the metal. The superheater flue is
3-in. part until the ends overlap, and the shape 5/8in. by 20 gauge. Clean the ends with coarse
is as shown. Put three or four rivets in the joint, emery-cloth ; the more you scratch it, the better
to hold it whilst brazing. Fill up the gap under the silver-solder will “ take.” Fit the tubes into
the combustion chamber with a piece of 1/16in. the end plate of the combustion-chamber, set
sheet copper, flanged over each side, bent at them level and parallel with it, and put the
bottom as shown, and riveted in place. The door- smokebox tubeplate on the outer end, to act as
plate is a small edition of the boiler backhead, spacer and support whilst silver-soldering.
made from 16-gauge copper and riveted in posi- Smear some wet flux around the tubes ; and if
tion. The firehole ring is made from a piece of you are using sheet silver-solder, cut a few tiny
1-in. by 1/8in. copper tube, with a step turned at 1/8in. squares and put a couple at each tube.
each side of it, and then squeezed oval. The Blow the lot to bright red, and the silver-solder
will melt, “ flash ” around the tubes and form a
G A U G E CLASS perfect seal. This is usually denoted by a silvery
ring showing around each tube, on the inside of
i the tubeplate. Before -pickling, pull off the
smokebox tubeplate, and heat the tube ends to
-3” -7Tz-kd dull red, to soften them for the expanding
UNDER CAB SILL
T h e backhead process ; then pickle the lot, and wash off.

step on one side is pushed through a hole in the First Stage of Assembly
door-plate, cut to receive it, at position shown ; All contact surfaces should be cleaned with
and the lip is hammered down on the flange
side of the plate. Fit two 16-gauge top girders coarse emery-cloth or other abrasive, and the
as shown. projecting bits of water-tubes filed flush with the
combustion-chamber. Then slide the firebox-
The combustion-chamber tubeplate is knocked and-tube assembly into the shell ; see that the
up from a bit of 16-gauge copper sheet, and firebox is central with the wrapper, and put
drilled as shown ; it fits over the end of the three or four 1/16in. copper rivets through the joint
chamber like the lid of a coffee-tin. Four 3/8in. where the two throatplates meet (see illustration).
by 22-gauge water-tube struts are fitted to the If the tops of the crown-stay girders are hard up
combustion-chamber, as shown. Leave plenty of against the inside of the wrapper sheet, let them
length on these when fitting, and slightly counter- bide ; if not, put a couple of rivets in to hold
sink the holes. Then braze up the whole issue them in contact whilst silver-soldering. Next,
at one heat, running a good fillet of brazing fit the smokebox tubeplate, flange outwards as
material around the water-tubes and the firehole shown; the tubes can be guided through the holes
ring. The melted metal should also fill up the by aid of a wooden meat skewer, knitting needle,
grooves between end plates and firebox sides ; or blacklead pencil. When the flange is halfway
also leave a fillet where the little throatplate in, the tubes should be about 1/32 in. through.
joins the underside of the combustion-chamber, Expand them by driving something taper, such
and at each side of the roof girders. A little as a drill shank, into the ends ; if greased, it
silver-solder may, if desired, be run under the will come out easily. The joints can then, be
girder flanges, to make certain that the contact is silver-soldered. Use a coarse grade of solder
perfect, and that the flanges cannot pull away and a good borax flux, such as “ Tenacity
from the firebox crown. This also makes a No. I,” mixed to a paste with water ; with a
certainty of sealing the rivets. 2-1/2pint lamp, no coke packing will be needed for
this job. Just lay the boiler in the coke in the
The smokebox tubeplate is merely a circular pan, heat up the end, run a little silver-solder
516 into that part of the flange joint which is upper-
most, and turn the boiler over to do the other side.

Stand it on end to do the tube ends ; use best-

grade silver-solder, or “ Easyflo ” for these.
Then turn the boiler on its back, with the fire-
box overhanging the edge of the pan, and run
some silver-solder along the joints between
flanges and wrapper. If you flux the joints, and
lay a strip of silver-solder alongside each flange,
a good hefty blow from underneath, outside
of the wrapper, should heat the whole issue to a
medium red, and make the silver-solder melt and

THE MODEL ENGINEER APRIL 13, 1950
sweat clean through each joint. If you have a pany whilst the final silver-soldering is going on,
smaller blowlamp as well, get that going, and Three 3/32-in. copper wire stays pass through
play on the girders with the flame, at the same plain holes in the wrapper, and are riveted over
time. The job will then be just a cakewalk. Let at each side, as shown in the cross section.
cool to black before putting the job in the pickle ;
and beginners especially note--mind the splashes. Fill in the gaps between firebox, wrapper,
If any splashes get on your skin, wash off imme- and backhead, with pieces of 3/16in. soft square
diately, or you’ll get the itch without wanting copper rod, well cleaned, holding them in place
to build a Tich ;and if your clothes get splashed, by three or four 1/16in. copper rivets in each.
liquid ammonia (as used for washing) is a good Drill the holes in the barrel for dome and safety
antidote, and may save patronising CC41. valve bushes, and fit bushes turned from thick
copper tube, or copper rod ; failing that, bronze

3/32 B E A R E R S

FRONT ENO

I UNDERNEATH I %;OR7BA
BARS
2’ ‘ii I‘14

SPACERS
‘/a T H I C K

iiE X C E P T

I

Grate and ashpan

Backhead and Foundation Ring or good gunmetal. Brass bushes are liable to
The backhead is knocked up from 13-gauge melt. Maybe our approved advertisers would
supply small pieces of cast copper, or the metal
(3/32-in.) copper. If this thickness is used, used in plumbers’ weldable fittings, as used in
there will be no need for putting in bushes for modern copper all-welded plumbing. When our
the fittings, with the exception of the regulator. old friend, Mr. H. C. Sturla, was running his
This needs a bush, as it must go in parallel with foundry at Waltham Cross (the foundry is still
in active operation, though “ Bro. Smiler ” has
the top of the firebox wrapper ; the bush is long since retired), he gave me much valuable
information about the composition of various
5/8 in. diameter with a 9/32 in. clearing hole in it. alloys. There are hundreds of grades, and I
The illustration shows how it is fitted. The
position of the firehole is obtained from the honestly believe he knows every one by heart !
boiler itself, measuring from firehole ring to top
and sides of wrapper, and transferring the What was more valuable still, he used to give
measurements to the backhead. I have stressed me sticks of metal, of the absolutely correct
many times, to cut the hole a bit undersize at
first, then try the backhead in place, and file the grade for any purpose I required ; and even at
hole as indicated by the flange. When you get
it in correct position, put the backhead in place the present time, I still have sufficient of his
“ for keeps,” and flange out the lip of the firehole cast copper stick metal, to turn quite a lot of
ring, where it projects through, hammering it boiler bushes. Most of my locomotives have
down into close contact with the backhead. pistons turned from his special bronze-maybe
Beginners note that this forms a nobby stay to that is why they go for years without attention,
the door-plate of the firebox. If the sides of the
wrapper won’t keep tightly in contact with the and never let a whiff of steam get by !
backhead flange, hold them in place with a
clamp, or in the bench vice, and put a few stubs On this wee boiler, silver-solder can be used
of 3/32-in. copper wire,screwed 3/32 in. or for the final braze-up, and as it is the last opera-
7 B.A. through wrapper and flange. That will tion in that line, best grade can be used. I
teach them manners, and they won’t part com- recommend “ Easyflo ” and the special flux sold
for use with it ; not because I’ve any shares in

the firm of Johnson-Matthey (I wish I had ! !)

but because I use the stuff myself, and find it
517

THE MODEL ENGINEER APRIL 13, 1950
absolutely the “ cat’s whiskers.” One of the this makes for clean threads. The die should
reasons why my little boiler fittings look like also be treated to a dose of the same medicine
jewellery jobs, is because they are silver-soldered when screwing the 3/32-in. copper wire used
with “ Easyflo ” wire. The job is done in the for stay bolts. Directions for stay-making and
same way that I have fully detailed out for larger fitting have been given umpteen times already.
boilers. Put the boiler on its back in the coke, Screw the bits of wire for about 7/16 in. length,
after covering all joints with wet flux, and pile and screw right home through the holes in
the coke around it almost level with the founda- wrapper. Use ordinary commercial brass nuts,
tion ring. Put a bit of asbestos millboard inside and any thread projecting beyond, may be
the firebox, to protect the combustion chamber snipped off close to the nut. This will become
burred when riveting over the outer ends of the
, I.. __ BEND ON -t- stays, and the nuts will be unable to slack back.
“I DOTTED LINES The throatplate stays should be put in parallel
with the boiler barrel, so that the nuts lock up
squarely against the firebox front plate.

Sweat over the stayheads and nuts by heating
the boiler to the melting point of soft solder,
and then brushing the liquid solder all over the
inside of the firebox, using plenty of liquid flux ;
not paste flux on any account. The outside can
be done in the same way. Be careful to well wash
away all traces of the soldering fluid, or the
copper will turn green and show signs of corro-
sion. The boiler can then be tested by water
pressure, to 160 lb. in exactly the way described
for larger boilers.

How to cut and bend ashpan Grate adn Ashpan
As the notes on this little boiler have panned

out a shade longer than anticipated, I will, all
being well, deal with the differences in the
fittings and mountings, in a following final
instalment, showing a suitable feed-pump at
the same time ; meanwhile, builders can make
the grate and ashpan. The grate is composed

and tubes. Then get busy with the blowlamp. i8c t :
Use two, if you have them, getting a mate (even CUl \ I$ CUT
a kiddy will do) to play the flame of No. 2, :OPPER
along with your own, on the opposite side of the
joint, catching same literally “ between two SLOPE OF :
fires.” After a preliminary heating, start con-
centrating on one corner, and when that is hot 7’ FIREBOX ’
enough to melt the strip of silver-solder when AFTER /
applied, work all around, inch by inch. Then
up-end the boiler and do the backhead flange BENDING.;
and firehole ring ; finally run a fillet around the
bushes and the heads of the wire wrapper stays. I
When it cools to black, be careful how you put
it in the pickle, as it is now fairly heavy ; and I
when the acid runs inside for the first time, it
usually emulates a geyser or a whale. Let it -cu1 :
/
stay in the pickle for 20 to 30 minutes ; /

then fish it out, drain well, wash in running water, How to cut out firebox and combustion
and clean up. I have already explained how to chamber
test for “ pinholes,” and what to do if you find
any.

Staying of ten 1/4in. by 1/8in. firebars, mounted on 3/32-in.

With the construction, and thickness of metal bearers, the spacers being 7/32-in. washers,
specified,, there won’t be any need of either 1/8in. thick, drilled No. 40. Four or six of the
longitudmsl stays, or screwed cross stays in spacers at one end of the grate should be a little
the firebox wrapper ; and with the spacing thinner, as the grate should taper 1/8in., to suit
. shown, only 3/32-in. or 7-B.A. stays will be the firebox. Maybe our approved advertisers

needed in the firebox. As the combined thickness will supply a cast grate ; I have received some
of wrapper and firebox sheets, plus the water excellent samples of grates for other engines,
space is less than 5/16 in ordinary taper and from our Scottish friend “ Wilwau.”
second taps will do the trick, and no special tap A diagram is given of the ashpan “ in the flat.”
is needed. Tip for beginners : wet the-No. 48 If this is cut from 20-gauge sheet steel, and bent
drill, and the taps, with cutting oil before using ; (Continued on page 523)

518

THE MODEL ENGINEER

Fig. 3

cheeks could be fitted accurately embracing the felt that both screw-feed and lever-feed for the
rectangular guide bar of the bed. back poppet were called for, the former for
drilling with twist drills of 1/16 in. to 1/4 in., and
However, in this case a radial saw-cut was the latter for use with watchmaker’s drills. For
provided out of the $-in. diameter tunnel, and a the screw-feed I prefer the pattern which employs
locking screw and lever. The latter was arranged an internally-threaded barrel, from which the
either to clamp the tailstock by moving the top centres or drills can be automatically ejected on
of the lever towards the headstock, or to give withdrawal. This is, however, a type which I
a positive unlocking action on reverse movement had never seen combined with a lever-feed
by means of a small flange on the locking-screw movement ; the design did not present any
trapped behind the rear cheek-plate. particular difficulty, as may be seen from Figs. 3
and,,4 (a) and from the photograph.
Lever-feed or Screw-feed at Will
In a lathe of this “ in-between ” size it was (To be continued)

“ L.B.S.C.” (Continued from page 518)

on the datted lines, it will finish up as a hopper silver-soldered in place. The lower part of the
of the correct shape, size, and slope. Stand it pin passes through the hole in the front member
on end, narrow end down, on a piece of the same of the pony truck, and is nutted underneath.
kind of material, and braze the joint, using When the ashpan is in place, the upper part of
Boron compo or similar flux, and brass wire ; the pin enters the blind hole in the rear cross-
trim to shape, The closed front end prevents brace of the main frames, and transmits the pull,
ashes and grit getting at the working parts of the via the pony frame, to the drawbar, which is
engine. At I in. from the front, a piece of spring attached to the rear cross-brace of the pony
steel (clock spring will do) is riveted to the ash- frame. The ashpan is kept in position by a
3/32-in. pin, passing through a hole in each
pan, and bent to the shape shown ; the ends of top flange, through corresponding holes in the

this, bear on the cross stay of the pony truck, projecting part of the firebox side sheets ; an
and take part of the weight of the trailing end of
the engine. A bracket made from 16-gauge steel, arrangement which works very well on one of
cut out to shape shown, is riveted to the underside my own engines. The grate is mounted on
of the ashpan at the closed end ; see side and four legs attached to the ashpan, as clearly shown,
underneath views. This carries the pony king- so that the whole lot-grate, ashpan, and pony
pin, made from 1/8in. round steel, and brazed or truck-are released by pulling out the pin.

523

A " Bonny” Job! by " L.B.S.C."

T HE boys up North surely know how to do some of the components for the boiler, which is
it, as the reproduced pictures will show. made as per my usual practice, and steams like a
This engine was by way of being a long job ; witch. He also did the painting and lining.
not the builder’s fault, I hasten to add, the delay Incidentally, although I have already seen plenty
being mainly due to a certain late and unlamented of pictures of small engines with “ British Rail-
party who was known as Adolf the Unworthy. ways ” on their tenders and tanks, up to the time
She is, as you can see, a one-sixteenth edition of of writing I haven’t seen one with the lion and

Mr. C. Lampitt’s “ Blink Bonny ”

the first lot of Gresley Pacifics, and was started wheel on it. I’ve a sneaking regard for that poor
before the war. At that time, the only available old animal, he is so typical of the British people,
drawings were a set got out by a designer who looks as though a jolly good feed would do him
a world of good, yet he always keeps his tail up
has also departed hence ; consequently, the and always faces toward the front of the engine.

engine only has two cylinders, and some of her Blink Bonny collected her racehorse name by
components don’t agree with modern practice. virtue of really being bonny, and she certainly
However, the builder, Charlie Lampitt, of Leeds, “ makes them blink.” She is a first-class worker,
got started on the job, and made steady progress no trouble to keep in steam for hours at a stretch
until the war stopped him. After hostilities were when necessary, as when working on an exhibition
over, he got busy once more, but this time with track hauling heavy loads. A typical example
a difference. Your humble servant had started of what she can do, was shown on August 24th
to describe a L.N.E.R. Pacific, and our worthy last, at the Leeds City Police Gala, on their
friend took the notes as a guide, with the result sports ground, the line being the Leeds Societies’
that although externally she follows the lines of Miniature Railway. She was lit up at 3.30 p.m.,
the original design, the things that matter are all and was in steam until 8.15 p.m., running con-
in accordance with these notes, and the result tinuously. She carried 843 passengers all told,
is satisfactory, “ with knobs on ” as the kiddies most of them kiddies, but for a test she hauled
would probably say. six of the heaviest Leeds bobbies present at the
gala, and without the least distress. Among the
There is no need to describe the engine in drivers were the Lord Mayor of Leeds, and the
detail, as the photographs show practically every- Chief Constable. Tlne above explains the tem-
porary coupling-fork in the tender buffer beam.
thing of importance ; and the machining, fitting, The ordinary coupling isn’t strong enough to
stand the racket, so the temporary one is put in
and other work entailed, were done in the manner for heavy hauling, and her owner forgot to take
usually observed among painstaking and cons- it off before she was photographed. The engine
cientious locomotive builders. Charlie was lucky is certainly a credit to her builder and his friend.
in getting a little assistance in finishing her off,
from another brother of our craft who is too shy 665
to have his moniker in print, though up at Leeds

they all know him well-‘nuff sed ! He made

THE MODEL ENGINEER MAY II, 1950
He Was a Craftsman! somewhat similar to the way our late brother
built Como ; Al sent him some photographs,
May I add my humble tribute to what has and in one of his letters afterwards, J.B. told me
already been written about the late Dr. John he had spent an exceedingly pleasurable time
Bradbury Winter, as he was my great friend, and going over them with a powerful magnifying
I was in correspondence with him to the last. glass, but could find no fault with the workman-
He used to visit me occasionally, when living at ship. Also, he said that he felt a great pride,
Sheen, and when he and Dr. Hovenden and your inasmuch as his own efforts had stimulated
humble servant started talking about the old another brother of the locomotive craft, to do
L.B. & S.C.R., it was a non-stop performance, his best to emulate them ; and he meant just
that, as those who understood his personal
and a job to know when to leave off ! I’ll always

recollect one summer afternoon, when Drs.

A nice bit of lining and lettering

Winter and Hovenden, and Cecil Purdey, of character, would know full well. Praise from
Dr. Winter, was praise indeed-he was the one
sporting-gun fame-now, alas ! all on the other man above all others, fully qualified to give it,
by virtue of personal experience. By his passing,
side of rhe Great Divide-were running one of the world has lost, not only one of its most
my engines. Dr. Hovenden was driving, the expert craftsmen, but a lovable, kindly person-
other two on separate cars. An up goods train, ality, the like of which is fast disappearing from
hauled by an old Brighton “ Vulcan ” running this benighted planet.
tender first, stopped by signal right opposite
my little railway ; and the driver, seeing the “ Diana “-Final Details
little engine sailing merrily along with its live The reproduced drawings show a boiler feed
load, blew his whistle and waved. Dr. Hovenden
blew the little engine’s whistle in reply, and pump which is not only suitable for Diana, but
waved so vigorously that he lost his balance, for any gauge “ 1 ” locomotive which has room
got the whole train off the road, and nearly put enough for it between two of the axles. There is
his passengers in the ditch, much to the amuse- no need to describe it in full detail, as the con-
ment of the full-size crew. When my friend, struction is precisely the same as I described very
Rob Morse, lived at Woodmancote, Sussex, minutely for Tich ; and incidentally, I might
the two locomotive medicos used to go down remind new readers that I started giving fully-
there occasionally to drive his 9-1/2in. gauge detailed instructions, even down to drill sizes,
Stroudley tank engine Ranmore ; and, in the for locomotive-building, way back in 1924.
words of a well-known radio comedian, “ a jolly Briefly, the pump is a reduced version of what one
good time was had by all.” might call my “ standard ” type of pump ; tried,
tested, not found wanting in any respect whatever,
I put the worthy Doctor in communication and entirely free from complication of any sort.
with Al Milburn, who is cutting his 3-1/2in. gauge
Atlantic engine out of the solid, in a manner
666

THE MODEL ENGINEER MAY II, 1950
It also contains the absolute minimum number of off the shoulder to the same angle as the point
parts. The body can be made either from a cast- of the drill used for drilling the pump barrel.
ing, or from 5/16in. round bronze or gunmetal In case anybody reading this, hasn’t seen my
rod. The casting is machined up as described for description of the pump for Tich, and wonders
Tich.If made from rod, part off a 7/8in. length, and what this pip is for (sometimes it is called a
drill, ream and tap it to form the valve-box, just “ pintle “) it enters the hole at the extreme end
the same as the casting. Then at 3/8 in. from the of the pump barrel at the end of the stroke, and
suction end, drill a 3/16in. hole in the side, and fit expels any air that may have become trapped in

No 40 DRILL

Special small side clack

3/32 OR 7 BA.

Details of pump for “ Diana ” Simple top feed fitting

a separate barrel into it, the barrel being also made the pump. I call it the “ anti-airlock pin.”
from 5/16in. rod. Chuck a piece truly in the three- Note, it is only needed when the hole at the end
of the barrel is smaller than the ram. If the 3/16in.
jaw ; face, centre, and drill down about 3/4 in. bore of the barrel were continued right into the
space between the valves, spreading them much
depth with a 7/64-in. drill. Screw 1/2 in. of the farther apart, the anti-airlock pin would not be
outside with a 5/16in. x 32 die in the tailstock needed, as the pump ram itself would be arranged
holder. Open out to 9/16 in. depth with 3/16in. to go as far as the centre-line of the valve-box at
drill ; part off at 11/16 in. from the end. Reverse the extreme inward end of the stroke, and would
in chuck, and turn down 1/8 in. of the end, to a thus expel any air ; yet some good folk insist
on adding the pip in a full-bore barrel, probably
tight fit in the hole in the side of the valve-box ; because they imagine it is specified in my pumps
for some reason that I haven’t explained, and
squeeze it in, and silver-solder it. The valve
balls; top and bottom caps, and gland nut are the pump might fail without it !
made and fitted as described for Tich ; don’t
forget to nick the bottom ball chamber under the The outer end of the ram is slotted and cross-
barrel, so that the ball cannot block the hole drilled, as per Tich instructions, ditto the eccen-
when it lifts, preventing water entering the tric-strap and rod ; but as the eccentric has to
barrel. fit in the space between the two stop-collars,
and this is only 3/16 in. wide, there is no room for
The ram is a piece of &-in. round rustless steel a boss for the set-screw. Therefore, drill a No. 40
or hard-drawn bronze, 1-3/16 in. overall length.
Chuck truly in three-jaw, and turn down a full 667
1/8 in. of one end, to 3/32 in. diameter, bevelling

THE MODEL ENGINEER MAY II, 1950

hole in the thickness of the eccentric, tap 1/8in. branch of which, a pipe goes around the boiler
or 5-B.A., and fit an Allen screw if you have one barrel either to side clacks or top-feed fitting.
that size ; failing that, a grub-screw. The The pipe from the back end of the tee on the
gudgeon-pin is a piece of 3/32-in. silver-steel pump, goes to the by-pass cock, or screwdown
turned down to 1/16 in. at each end, screwed 1/16in. valve, whichever you like to fit. The pipe from
or 10-B.A., and furnished with commercial nuts. the bottom of the pump is led alongside it, both
terminating under the cab sill, which takes the
Although the illustrations show the pump place of the drag-beam on the ordinary type of
stay as a casting, dimensions being given on engine. Take the pipes out below the rear stay
them, I usually make these small stays by merely or brace at the back of the main frames, and
along by the side of the firebox, just clear of the
ashpan. You won’t need a drawing for that

simple job ! Make up the lengths of pipe, fit

the unions, and attach them before the boiler is
fixed “ f o r keeps.” The pipe for connecting up
the hand pump can be put on after fixing the
boiler, as it merely goes from the union under
the cab, as direct as possible to the clack on the
backhead.

How to Erect Boiler and Cab

The smokebox end of the boiler is fixed exactly
as described for Dot ; but the rear end has a
single transverse plate bracket arranged after the
style of the Ivatt Atlantics on the old Great
Northern Railway. At the front end of the firebox,
the inner plate projects 1/4 in. below the outer
Pump stay and eccentric plate, both on the slope. Right in the middle of
this projection, bend a little over I in. of it so
bending a piece of brass sheet of requisite thick- that it is vertical, at right-angles to the bottom
ness, to a shallow-channel_ shape, just wide
enough to fit between the frames. It is easily
done in the bench vice, if the metal is annealed BEND TO
A bent-up stay is very neat. The pump is erected BOILER CONNECT TO TEE

between the driving and trailing coupled axles,
the valve-box being set to clear the trailing
coupled axle by 3/32 in., as shown in the plan
and sectional illustrations. I have already
explained how to get the exact length of eccentric-
rod, to ensure 1/32 in. clearance between end of EXTENSION
ram and end of barrel. The little eye should be HANDLE THROUGH

FOOTPLATE

case-hardened, for long wearing.

Pipe Connections RUN FEED AND BYPASS PIPES
Before permanently erecting the boiler, the ALONG BOTTOM OF FIREBOX

pipe work, or plumbing, as our cousins over the Diagram of pipe connections
big pond call it, should be tackled. The diagram
shows the connections. First, make up two of the boiler barrel. This is easily done by
weeny side clacks to go on the boiler barrel, or catching hold of it with the jaws of a good hefty
a top-feed fitting, just as you prefer. If the side pair of flat-nosed pliers, and judiciously applying
clacks are used, tne stems can be screwed into a little “ Sunny Jim ” in the required direction ;
tapped holes in the thickness of the boiler shell, as the copper is quite soft after the final brazing
and soldered ; this will be quite all right, as they process, it is amenable to this treatment. Two
never need to be removed. If the top-feed or three bites may be needed, according to the
fitting is used, a bush is needed to screw it into, width of plier jaws ; a hand-vice could also be
as it may need removal for cleaning. The bush used, and if the jaws of it are I in. wide, same as
could be silver-soldered, when the dome and my own vice (not being a retailer of stale jokes,
safety-valve bushes are being attended to; I didn’t leave out the word “ vice ” after “ own ” !)
or it may be screwed into the thickness of the the deed can be accomplished at one fell swoop.
boiler barrel, and soft-soldered, which is quite Cut a strip of 18-gauge brass or copper, I in.
in order for such a small boiler. long and 1/2 in. wide, and rivet it to the bent part
by four 1/16in. rivets. Drill three No. 40 holes in
To get the required lengths of pipe, I usually the piece of strip below the firebox ; and when
put the boiler temporarily in place, and run bits
of lead wire of requisite diameter, between the
starting and finishing points, as I have several
coils of lead wire, and no special use for it.

Ordinary copper wire can, of course! be used ;

these wire templates save wasting precious copper
pipe. From the forward end of the tee on the
pump, a pipe goes to another tee,from each

668

THE MODEL ENGINEER MAY II, 1950
the boiler is placed in position, run three 3/32-in. the weary ! To prevent the cab having the
or 7-B.A. screws through the holes, into tapped appearance of being suspended in mid-air
holes in the stay. Put a short screw in the middle when seen from the side, a make-up piece (see
one, so as to leave the hole for the king-pin general arrangement drawing) can be cut from
on the pony truck, quite clear. The whole doings sheet brass and fixed to the underside of the foot-
is shown in the illustration. The strip of metal plate, at each side of the cab, between backhead
attached thus, is flexible enough to take care of and sill. Simply bend over the top, and rivet to
the expansion stresses in such a little boiler,
but at the same time ensures a sound and strong the underside of the footplate ; or merely solder
attachment.
it, if you like, as it only needs to be strong
Cut the cab footplate from a piece of 18-gauge
sheet metal ; brass or steel will do equally well. c
It may be either cut short at the back of cab,
level with sides, or extended back almost to Plan of cab footplate
touch the front plate of the tender, as shown in enough to “ stay put,” and carries neither weight
the various views of the mock-up of the new nor stress. The only alteration needed to the
standard B.R. cab shown in several “ full-size ” Dot tender, is to leave out the spirit tank, fit a
sloping bottom to the space it occupied, for carry-
journals ; this extension is shown dotted in
ing coal ; and add feed and by-pass pipes.
our illustration. Leave the gap for the fircbox
Well, I don’t think there is any more to say
a bit on the small side when first cutting out ;
about the weeny-weeny Pacific ; but frankly I
then attach the footplate to the bottom of the
cab sides by small pieces of angle, either riveted am surprised at the way Dot and Diana have
or soldered, whichever you prefer. The next “ caught on.” I just included them as suitable
job is to fit the cab to the boiler ; that calls for for an indoor “ scenic ” railway, perhaps to
a little patience. My own pet antic is to make a amuse and interest “ railway-conscious ” kiddies,
template from thin cardboard or stiff paper, and
it takes very little time to fit this to the boiler, \ B E N D P A R A L L E L TO F R A M E S T A Y J

iN I

Ashpan fixture I-
after which it is laid on the metal, a scriber run How to fix rear end of boiler
around the “ arch,” and the sheet metal cut to and even give them a ride on an outdoor line ;
the scribed line. The result is invariably an but I find that builders are making a reaIly serious
excellent fit. The sides of the gap in the footplate job of the tiny engines, and have just heard that
may be eased with a file until they fit snugly there has been quite a rush on the blueprints.
against the sides of the firebox wrapper. Maybe the fact that they are cheaply, easily, and

All that is needed to fix the cab to the boiler quickly built, has a lot to do with it ; my experi-
is a bit of angle about 1-1/2 in. long, riveted to the
underside of the footplate, level with the edge of ence is that 99 per cent. of locomotive builders
the firebox gap, and screwed to the backhead. would rather get the wheel turning, and the safety-
As the latter slopes, the angle is sharper than a valves sizzling, than spend years in making useless
right-angle, so bend up the needful from a bit fallals, so I try to cater for their needs.
of 18-gauge brass about 1-1/2 in. long and 1/2 in.
or so in width, fitting it to the backhead and foot- 669
plate, so that it lies snugly against each. The sill
can be attached to the underside of the footplate

by a similar piece of angle, riveted to both ;

in this case a right-angle is required. The pipes
are attached to the underside of the sill by
brackets, same as I usually specify for the pipes

under the drag-beam of a larger engine ; but

keep them as low as possible, and it would be an
advantage to bend down the ends, also bend
up the ends of the pipes coming out from under
the tender to match, SC that the hose couplings
won’t kink. I see that, according to the mock-up
pictures already referred to, my usual arrangement
of pipe connections between engine and tender,
to enable any tender to be used with any engine,
isn’t going to be of any use on the new B.R.
standard locomotives ; so I’ll have to scheme out
a new wheeze for pipe connections. No rest for