Turning workpiece

151

SELF CHECK

TEST REVIEW EXECRCISES

Select the best Answer. Write the letter of the correct answer o the blank
provided before each number.

_________ 1. The operation to procedure several diameters on
a. Turning straight diameter
b. Taper turning
c. Recessing
d. shoulder turning

__________2. A shoulder with rounded corner turned to a specific radius is
a. angular
b. filleted
c. square
d. undercut

__________3. The shoulder produce at right angle to the small diameter
a. filleted
b. angular
c. undercut
d. square

__________4. An angular shoulder is produced with a
a. facing tool
b. form tools
c. square nose tool
d. round nose tools

__________5. The best method of laying out length of shoulder with workpiece
mounted between centers is with the use of
a. steel rule and scriber
b. hermaphrodite
c. divider
d. trammel

152

Direction: This form should afford the Instructor to rate the
Productivity/Performance of the trainee for a give Employable
Skill/Activity/Project. On the space provided for, write the points which likely
coincide with your evaluating for each of the following factors: Outstanding – (4
pts.); Plus Satisfactions – (3 pts.); Satisfactory - (2 pts.); Below Satisfactory –
(1 pt.)

SATISFACTORY TASK PERFORMANCE REQUIREMENT FACTORS Rating
Provide with MS Drawing Nos. 103, 108 ,109, 119 and 124, A. Quality/Appearance
complete tools and materials the trainee should be able to
(symmetry; Verticality;
1. Turn shoulders of Horizontality ;
1.1 stepped shaft Workmanship,
1.2 tap wrench handle Finish)………….
1.3 marking gauge flange B. Accuracy/Critically (
1.4 marking gauge shaft Exactness of
1.5 turning exercises dimension/specification,
High, medium,low,
2. Finish turn approximately six (6) hours critically)
C. Speed (50% over
estimated time . . . – (1
point) (50% time save
over estimated . . . and
(1 point) . .

D. Method

(Economical: use of

tools ; Safety and

hygiene, Initiative)
…………….

TOTAL POINTS …………….. _____
GRADE ………………………._____

REMARKS: Working hours is approximately one (1) hour.

By:___________________________

____________________________

Designation

153
Operation Title: Recessing
Purpose:
Condition or Situations for the Operation

External recessing (Figure 1a), is the operation of machining a smaller
diameter on a workpiece for a specified length. Internal recessing (Figure 1b), is
the machining of a larger diameter for a specified length inside a hole. Recesses
may have squared or rounded corners depending on where they will be used.
Recesses are produced especially on parts of a machine which require material
fillings.

Figure 1. Example of External and Internal Recessing

154

TOOLS, EQUIPMENT AND MATERIALS

1. Tools
1.1 Recessing tools
1.2 Toolholder
1.3 Vernier Caliper
1.4 Outside Micrometer
1.5 Four Jaw Independent Chuck
1.6 Center or Tool Gauge
1.7 Hermaphrodite Caliper
1.8 Steel Rule
1.9 Safety Goggles
1.10 T-Wrench
1.11 Hook Rule

2. Materials
2.1 1 pc Ø 6.35 x C.R.S.
2.2 1 pc Ø x 34 C.R.S.
2.3 1 pc 25.4 Ø x 19.0 C.R.S.
2.4 MS Drawing Nos. 1 Ø 8 and 1 Ø 9

3. Equipment
3.1 Lathe machine

Procedure
Task No. 1 – Turning an external recess of a shaft

1.1 Study the drawing of the shaft
- Refer to MS drawing

1.2 Clamp the workpiece in a chuck
a. Clean chuck jaws and check if they are properly centered
b. Clamp the workpiece providing minimum overhung. See Figure 2.

Figure 2. Mounting the workpiece in a chuck

155
1.3 Select and set-up cutting tool

a. Choose the right design of outing tool
b. Clamp and set-up cutting tool, Figure 3. Use a center gauge.

Figure 3. Setting-up tool using center gauge
1.4 Set-up speed and feed of machine

a. Select speed and feed of machine based from the
material of the workpiece

b. Choose the nearest speed on the machine date place
c. Set the speed with lathe controls, Figure 4.

Figure 4. Setting up machine speed and feed

156
1.5 Set the position of the too

a. Wind the cross slide so that the tool is approximately 0.5mm clean
of the workpiece diameter.

b. Align the required measurement on the rule to the end of
workpiece, Figure 5. the steel should be parallel to the workpiece

Figure 5. Setting up cutting tool to the correct position
c. The depth of a vernier caliper is also use to set-up the position of

the tool Figure 6.

Figure 6. Using the Vernier Depth Bar to set-up tool position

157
1.6 Turn recess to specification

a. Start the spindle and let the tool touch the workpiece diameter
b. Set the cross slide micrometer collar to zero
c. Turn on coolant and feed in the tool to a depth 0.1mm less of the

specified depth of recess, Figure 7. Use hand feed.

Figure 7. Setting up the depth of cut.
d. Stop the spindle and check the diameter of work with a micrometer.

See Figure 8

Figure 8. Measuring external diameter with micrometer

158
e. Check the length between end of workpiece and start of recess,

figure 9.
- The saddle may be move to adjust the length if require

Figure 9. Checking length using a steel rule.
f. engaged the automatic feed, then allowed the tool to cut along the

workpiece.
g. Disengaged feed when the tool is about 0.5mm from the required

length. See Figure 10.
- Finish the length of recess using hand feed.

Figure 10 Cutting an external recess

159
h. Withdraw the tool from the workpiece and bring it back on the

starting point to take the finish cut, Figure 11.
Remarks: Refer to figure 10. Show that the cutting tool is at the
starting point.

Figure 11. Setting-up the tool take finish cut.
i. stop the spindle and check length of recess. See Figure 12.

Figure 12. Checking dimensions of recess using a Vernier Caliper.

160
j. Check the diameter of recess with an outside micrometer. Refer to

Figure 8.

Task No. 2 – Turning the recess with an outside micrometer. Refer to
Figure 8.

2.1 Study the drawing of the marking gauge flange
- Refer to MS Drawing No. 108

2.2 Clamp the workpiece in a chuck
a. Clean chuck jaws and check if they are properly centered.
b. Clamp the workpiece providing minimum overhang like in Figure
14.

Figure 14. Clamping the workpiece in a chuck
2.3 Select and set-up cutting tool.

a. Choose the correct design of recessing tool.
b. Clamp and set-up recessing tool, Figure 15.

Figure 15. Setting-up tool using a center gauge.

161
2.4 Set spindle speed and feed of machine

a. Select speed and feed from the table
b. Locate the nearest speed and feed form the machine data plate
c. Set the speed and feed with lathe controls. Refer to Figure 14.
2.5 Set the position of the tool
a. Wind the cross slide so that the tool is approximately o.5mm
clear of the workpiece diameter.
b. Mark out the length of recess using a steel rule or a vernier

caliper. See Figure 16.

Figure 16. Laying out length of recess using a vernier caliper.
2.6 Turn recess to specification

a. Start the spindle and le the tool touch the workpiece diameter.
Figure 17.

Figure 17. Positioning tool to set-up micrometer collar to zero.

162

b. Set the cross slide micrometer collar to zero.
c. Turn on coolant and feed in the tool to a depth 0.1mm less of the
specified depth of recess, Figure 18.

Figure 18. Rough turning of the recess

d. Stop the spindle and check the diameter of recess with a
micrometer. Refer to Figure 8.

e. Check the length of recess using the steel rule or a vernier
caliper. Refer to figure 9.

f. Re-start the spindle, engage the automatic feed and allow the
tool to cut along the workpiece.

g. Disengage feed when the tool is about 0.5mm from the required
length. Refer to figure 10.
- finish the length of recess using hand feed.

h. Withdraw the tool from the work and bring it back to the starting
point and take finish cut.

i. Stop the spindle and chuck dimensions of recess. Refer to Figure
8 and 10.

163

Task No. 3 – Turn the recess of the marking gauge shaft

3.1 Study the drawing of the marking gauge shaft
- Refer to MS drawing No. 109.

3.2 Clamp the workpiece between contours, Figure 19.
- Protect finished diameter with soft metal stripes or shims.

Figure 19. Mounting the workpiece between centers
- The workpiece may be held also, in the chuck and center, see

figure 20.

Figure 20. clamping the workpiece in a chuck and center

164

3.3 Select and set-up cutting tool
a. Choose the correct design of recessing to be used
b. Clamp and set-up tool, refer to figure 3

3.4 Set-up spindle speed and feed of machine
a. Select speed and feed form the table
b. Locate the nearest speed and feed of machine speed plate
c. Set speed and fee with in the controls, refer to figure 4.

3.5 Se the position of the tool
a. Wind the cross slide so that the tool is approximately 0.5mm
clear of the workpiece diameter.
b. Mark out the length of recess using a steel rule. See Figure 21.

Figure 21 Laying out Length of recess
c. Position the tool on the scribed line, figure 22.

- a fine line may be made on the diameter using the point of the
tool, Figure 22.

165

Figure 22. Marking out a fine line

3.6 Turn recess to specification
a. Start the spindle and let the tool touch the workpiece diameter
b. Set the cross slide micrometer collar to zero
c. Turn on coolant and feed in the tool to a depth 0.1mm less of the
specified depth recess.
- Use hand feed
d. Stop the spindle and check the diameter of recess with an
outside micrometer. Refer to Figure 8.
e. Check the length of recess using a steel rule or a vernier caliper.
Refer to Figure 9.
f. Re-start the spindle, engage the automatic feed, that allow the
tool to cut along the workpiece.
g. Disengage feed when the tool is about 0.5mm form the required
length of recess
- Use hand feed to turn full length of recess
h. Withdraw the tool form the work and bring back on the starting
point to take the finish cut, see figure 23.

Figure 23. Turning recess to specification

a. Stop the spindle and check dimensions of recess. Refer to
Figure 8 and 10.

166

Task No. 4 – Turning an internal recess
4.1 Study the drawing of the workpiece
- Refer to MS drawing
4.2 clamp the workpiece in the chuck
- Provide minimum overhead
4.3 Select and set up cutting tool
a. Choose the form of tool to be used based on the specification
- Be sure that the cutting edge is sharp
b. Set up the tool on center
- Use minimum overhang

Figure 24 Correct set-up of an internal cutting tool

4.4 Select and set-up speed and feed
a. Set speed and feed with lathe controls
- Read possible values on the machine data plate

167
-----------------------------------------------------------------------------------

SAFETY NOTE
- Wear safety goggles
- Use guards
-----------------------------------------------------------------------------------

4.5 Turn the recess
a. Start the spindle and wind the tool to touch the surface of hole

Figure 25. Setting-up the tool into the hole.

b. Set the cross slide scale to zero
c. withdraw the tool from the hole and wind it to touch the end of
workpiece, Figure 26 (see next page)

168
- Stop the spindle and lock the saddle
- Note down the width of tool in preparation for the setting of the distance
of recess through compound rest
- Set the compound rest zero

Figure 26. Setting- up the tool against the end of the workpiece.

Figure 27. Positioning the tool into the hole
e. Set-up the distance of recess plus the tool width on the compound
rest scale. See Figure 28.

169

Figure 28 Positioning the tool to cut the recess
f. Star the spindle and feed in the tool to the correct depth of recess
using the cross slide scale (on the reverse the operator).

Figure 29 Turning an internal recess
g. Feed in the tool to the correct width of recess using the
compound rest.

NOTE:
The width of the tool should be smaller then the

specified width of recess

170

c. Withdraw the tool from the hole by moving the cross slide
away form the workpiece

d. Stop the spindle
e. Check length of recess using a hook rule. See Figure 30

CALL INSTRUCTION FOR CHECK-UP

Figure 30 Checking an internal recess

Precautions

IMPORTNACE

1. Clean tools and machines before and after using.
2.
3. Always apply machines parts with oil.
4. Maintain level of machine oil reservoir to keep machine in good condition
5. Always use coolant when taking roughing cuts to lessen load of machine.

171

TEST REVIEW EXECRCISES

Select the best Answer. Write the letter of the correct answer o the blank
provided before each number.

_________ 1. The smaller diameter that is machined to a specified length on a
workpiece is called
a. internal recess
b. external recess
c. filleted shoulder
d. angular shoulder

__________2. The process of machining a larger diameter of a specified length
inside a hole is called
a. internal recessing
b. external recessing
c. shoulder turning
d. boring

__________3. Recesses are produced on workpiece for :
a. cutting machine parts
b. joining two parts
c. special fitting on machine parts
d. Screwing machine parts

172

Direction: This form should afford the Instructor to rate the

Productivity/Performance of the trainee for a give Employable

Skill/Activity/Project. On the space provided for, write the points which likely
coincide with your evaluating for each of the following factors: Outstanding – (4
pts.); Plus Satisfactions – (3 pts.); Satisfactory - (2 pts.); Below Satisfactory –

(1 pt.)

SATISFACTORY TASK PERFORMANCE REQUIREMENT FACTORS Rating
Provide with complete tools, MS drawing Nos. 103, 108 adn109 A. Quality/Appearance
and materials with sizes Ø 12.7 x 150 CRS, Ø 68 x 34 and Ø 25.4
x 190, the trainee must: (symmetry; Verticality;
Horizontality;
Workmanship,
Finish)………….

1. Turn external recesses on the following parts/projects: B. Accuracy/Critically
1.1 Tap wrench handle (Exactness of
1.2 Marking gauge flange dimension/specification,
1.3 Marking gauge shaft High, Medium, Low
critically)
2. Working time should be within the Instructor specifications. C. Speed (50% over
Tolerance and surface finish should be within the specified limits. estimated time . . . – (1
point) (50% time save
over estimated . . . and
(1 point).

D. Method (Economical:
use of tools ; Safety and
hygiene, Initiative)
…………….

TOTAL POINTS …………….. _____
GRADE ………………………._____

REMARKS: Working hours is approximately one (1) hour.

By:___________________________
___________________________

Designation

173

Operation Title: Drilling

Purpose: To produce a hole in a solid material

Condition or situation for the Operation

Drilling is generally defined as the operation of producing a hole in
solid materials. Most of the drilling operations performed in the lathe are done
with the work piece mounted on chucks or clamped to the faceplate. Holes are
drilled in an opposite manner to the way holes are drilled on a drill is held
stationary.

Equipment, Tools and Materials
1. Tools,

1.1 Twist Drills (straight and tapered)
1.2 Combination Drill & Countersink
1.3 Drill Chuck
1.4 Chuck Key
1.5 Sleeve
1.6 Center Head
1.7 Hermaphrodite Caliper
1.8 Surface Gage
1.9 V- Block
1.10 Tool holder
1.11 Punch
1.12 Hammer
1.13 Faceplate
1.14 Lathe Chucks
1.15 Drill Pad
1.16 Crotch Centers
1.17 Adapter
1.18 Facing Tool
1.19 Tool Holder
1.20 T- Wrench
1.21 Dial Indicator
1.22 Steady Rest

2. Materials 3 Equipment
2.1 Cylindrical Stock 3.1 Pedestal Grinder
2.2 Flat Workpiece 3.2 Work Table
2.3 Working Drawing
2.3 Working Drawing 3.3 Surface Plate
3.4 Lathe Machine

174
Twist or shank dills are used to drill holes on the work but other types
like oil hole and straight fluted are also available for use. Drills may be held in
several ways while drilling is done on the lathe. Some of these are:

Figure 1. Using A sleeve To Hold A Tapered Shank Drill
2. Straight shank drills are usually held in a drill chuck mounted on the tail

stock spindle (Figure 2).

Figure 2. Holding A Small Size Drill In A Drill Chuck

175
3. A Lathe dog is used as a drill holder (Figure 3 when using a long twist drill.

The tail of the dog is rested on the compound rest.

Figure 3. Using The Lathe Dog As A Drill Holder
4. Another method to hold a large drill is with the use of a special drill holder.

The back of the drill is fitted against the tail stock center. Figure 4.

Figure 4. Using A Special Drill Holder To Hold A
Large Drill

176
5. In drilling holes on a flat workpiece, a drill pad is usually used, Figure 5.

The workpiece is carefully center punched and the position is adjusted by
turning the tail stock handwheel until the point of the drill hits the mark
(see figure 5 on the next page).

Figure 5. Using A Drill Pad To Hold The Workpiece
6. In drilling holes on any side of the workpiece body, the workpiece may be

held or supported with a crotch center. Figure 6. The crotch center is held
in the tailstock and the workpiece is forced against the drill.

Figure 6. Using A Crotch Center To Hold The Workpiece

177

It is important to know the correct speed at which the drill travels through
the material during the drilling operation. This only possible when a complete
data is available among others; the material of workpiece, the material of drills,
power and rigidity of machine and cutting fluid. The cutting speed affects the
cutting life of the drill. The table on the next page (Table I) will be useful in

determining the correct cutting speed when drilling on the lathe.

It may be observed that the recommended cutting speeds on the table
are given in English and Metric Units. The table shows that the slowest cutting
speed is recommended for the tool steel (a hard material), and the fastest
speed for the soft brass

Materials Recommended Cutting Speed

Mild Steel English Metric Units
Tool Steel
Cast Iron (Hard) Units
Cast Steel
Brass 60 ft. / min. 27 m/ min.

30 ft./ min. 15 m/ min.

40 ft./ min. 24 m/ min.

40 ft./ min. 24 m/ min.

200ft./ min. 60 m/ min.

Ft/min = feet per minute
M/min =meter per minute

Figure 7. Table Of Cutting Speeds For Drilling On
The Lathe

Center drilling is the operation of drilling and counter- sinking ends of a stock to
be held between centers. It provides bearing surfaces for the lathe centers.
Center drilling is done with the use of a combination drill and countersink (Figure
8).

The combination drill and countersink of center drill has an included angle
of 60%, the same angle the dead and live centers are provided with. The drill part
of this tool provides clearance for the center point and serves as a reservoir for
the lubricant.

178

Figure 8. A Combination Drill And Countersink
In selecting the correct size of combination drill and countersink, the
tables for standard sizes will be useful, see Figure 9 on the next page.

The tables shown in Figure 9 and 10 do not include the sizes of center
holes to be drilled because there is no rule, yet to determine such sizes. I the
absence of a rule, good judgment of the worker becomes an important factor.
The size of center holes also depends on the size of the workpiece. Figure 11

may be used to determine the correct depth of center holes.

179

Figure 11. A Comparison Of Correct And Incorrect Center Holes
1. Drilling center holes

1.1 Prepare tools and materials
a. Secure all the needed tools and materials for workpiece from the tool
keeper
-Be sure to check tools, replace with good ones if damaged
b. Secure the working drawing from the instructor
-Study it carefully and note down specifications
-Post the working drawing on the lathe before machining starts

180
1.2 Mount the workpiece in the chuck

a. Clamp the workpiece in the chuck providing just minimum overhang
b. Center the workpiece with a surface gage or dial indicator. Figure 12.

Figure 12. A Method Of Centering The Workpiece
1.3 Face one end of the workpiece

a. Select and set- up facing tools
-Be sure that it is ground sharp

b. Start the spindle and take outs
-Stops the machine when the operation is completed. WORKPIECES
WITH SMALL DIAMETERS ARE USUALLY FACED BEFORE
CENTER HOLES ARE DRILLED

1.4 Select a combination drill and countersink or center drill
a. Secure the correct size of center drill from the operation specification
-Check the sharpness of the center drill
-The drill tip should be sufficiently long to provide free movement from
the center point

1.5 Set- up the drill chuck and center drill
a. Fit the shank of the drill chuck in the tail stock spindle, Figure 13
-Check and clean the surface of the spindle hole and the tapered shank
of the drill chuck before mounting

181

Figure 13. Mounting The Drill Chuck In The Tail stock Spindle
b. Mount the combination drill and countersink, Figure 14

-Use a chuck key in loosening the drill chuck jaws
-Extend just enough length of center drill for center drilling
-Tighten the chuck jaws with a chuck key

Figure 14. Mounting A Combination Drill

182
1.6 Set the spindle speed

a. Select and set the spindle speed based from the operation specification
1.7 Drill the center hole

a. Move the tail stock until the point of the center drill is approximately
20mm. From the end of the workplace.
-Lock the tail stock to the bed
- Unlock the tail stock spindle

b. Start the spindle and feed in the drill by turning the tail stock handwheel
clockwise, Figure 15
-The drill should be fed into the workpiece slowly and with care

Figure 15. Drilling A Center Hole
c. Withdraw the center drill and clean chips with a brush
d. Check the hole and see if it is at the correct depth, Figure 16

183

Figure 16. Correct Depth Of A Center Hole
-Reverse the workpiece if the other and will be drilled
-If center holes will be drilled on a long workpiece, drilling is

accomplished by supporting the workpiece with a steady rest,
Figure 17

Figure 17. Drilling A Center Holes On A longer Work piece
-Another method of drilling center holes after the location of center is laid
out is by holding the center drill in the headstock spindle. One of the center
punch marks is held against the point of the tail stock center. The tailstock is fed
until the opposite end of the work piece lightly touches the drill, see Figure 18
(see the next page). A sufficiently fast speed is used.

184

Figure 18. A Method Of Drilling A Center Hole
-If any size of center drill is not available, a twist drill with a small diameter
and a countersink may be used.
2. Drilling through holes

2.1 Prepare the work piece
a. Secure the work piece from the tool keeper

2.2 Prepare the workpiece
b. Secure the workpiece from the toolkeeper
-Deburr the workpiece with a file

2.3 Mount the workpiece in the chuck
a. Clamp the workpiece in the chuck providing just minimum
overhang
b. Center the workpiece with a surface gage or a dial indicator,
refer to Figure 5.

2.4 Set- up the spindle speed with lathe controls
2.5 Drill the center hole

Face THE END OF THE WORKPIECE IF NECESSARY
-Refer to Task for details
2.6 Drill the through hole to specification
a. Select the size of twist drill based from the operation

specification or from the blueprint
b. Mount the twist drill in the drill chuck
c. Move the tailstock until the point of the twist drill is about

20mm. From the end of the workpiece, Figure 19
-Lock the tailstock to the bed
-Unlock the tail stock spindle

185

WORKPIEC TWIST DRILL
E
DRILL CHUCK

TAIL STOCK
SPINDLE

TAIL STOCK
SPINDLE

ABOUT 20 mm

Figure 19. Setting The Twist Drill

d. Start the machine and Slowly feed the twist drill by turning the
tailstock handwheel clockwise, see figure 20, until the drill has
reached its full diameter.
-Be sure to lubricants the drill.

Figure 20. Drilling A Through Hole

186

e. Black out the twist drill occasionally to free it from chips
-A lead hole should be drilled first when drilling a large hole

f. Continue the operation until the full length of hole is drilled
g. Stop the machine after the operation is completed and

withdraw the drill from the hole.

3.Drilling blind holes
3.1 Drilling blind holes
a. Secure the workpiece from the toolkeeper
-Deburr the workpiece with a f
3.2 Mount the workpiece in the chuck
a. Clamp the workpiece in the chuck providing just
minimum overhang

Figure 22. Setting The Twist Drill

c. Center the work piece with a surface gage or a dial indicator
(refer to Figure 5)

3.3 Set- up the spindle with lathe controls
-Read spindle speeds on the machine data plate
-Use the nearest spindle speeds

3.4 Drill the center hole
FACE THE END OF THE WORKPIECE IF NECESSARILY
-Refer to task 1 for details

3.5 Drill the blind hole to the specified depth
a. Select a twist drill based from the operation specification of
from the blueprint
-When drilling a large hole, a pilot hole should be drill, see
Figure 21

187

DRILL
CHUCK

TWIST TAILSTOCK
DRILL SPINDLE

WORKPIECE

Figure 10. Drilling A Pilot Hole

b. Mount the twist drill on the drill chuck
c. Move the tail stock until the point of the drill touches the

opening of the hole, see Figure 22 (see next page)
-Lock the tail stock to the bed
d. Start the spindle and feed the drill using the tail stock hand
wheel until a full diameter is cut, Figure 23
-Stop feeding and note down the reading on the scale of the
tailstock

WORKPIECE 188

DRILL TAILSTOCK
CHUCK SPINDLE

TWIST DRILL

MASURE THE
TAILSTOCK
SPINDLE

Figure 23. Drilling To A Diameter

e. Continue drilling and add the depth of hole required to the
reading obtained, Figure.

24 (see next page)
-Stop the spindle when the required depth of hole is reached

Workpiece Drill chuck

Tailstock spindle

Measure depth of Reading on the
hole spindle the required
depth of hole

Figure 24. Drilling The Hole To Specification

189

f. Withdraw the drill from the hole and measure the depth of hole
with a dernier caliper, Figure 25
-Be sure to break sharp edges before measuring

Workpiece

Vernier
Cali[per

Figure 25. Measuring The Depth Of Hole

IMPORTANT
1. Clean tools and machines before and after using
2. Place tools in the tool boxes or on the lathe headstock
3. Always maintain the oil level of machines.
4. Stop machines after an operation is completed

190

Quality Criteria

Select the best answer. Write only the letter of the correct answer on the
blank provided before each number.

_______ 1. The operation that is accomplish with the use of drill is
a. spot facing
b. countersink
c. drilling
d. center drilling

_______ 2. The tool that is generally used for drilling center or pilot holes is
a. twist drill
b. combination drill and countersink
c. flat drill
d. countersink drill

_______ 3. One method of accomplishing the drilling operation on the lathe is by
holding the work piece in the chuck while the drill is held in a

a. drill holder fastened to the tool post
b. mandrel fitted to tail stock spindle
c. drilling attachment
d. drilling attachment

________4. The sizes of combination drill and countersink are usually specified
by
a. capital letters
b. small letters
c. symbols
d. numbers

________5.Center holes must be drilled on both ends of a work piece that will be
straight turned to provide
a. bearing surfaces for lathe centers
b. easy layout for turning
c. effective use of cutting tool
d. correct set- up of work piece

191

Direction: This form should afford the Instructor to rate the Productivity/

Performance of the trainee for a given Employable Skill/Activity/Project. On the

space provided for, write the point that likely coincides -with your evaluation for

each of the following factors: OUTSTANDING- (4pts.); PLUS SATISFACTION-
(3pts); SATISFACTORY – (2pts).); BELOW SATISFACTIORY – (1 pt.)

SATISFACTORY TASK PERFORMANCE FACTORS
REQUIREMENT
RATING

Given the working drawing of tap wrench QUALITY/APPERANCE ––––––
handles, marking gauge flange, marking
gauge shaft, and step shaft, completed (Symmetry; Verticality; –––––––
tools and materials, the trainee should be –––––––
able to: Horizontality; ––––––
––––––
1. Drill center holes Workmanship,
2. Drill blind holes to specification Finish)…..

3. Drill through hole to ACCURACY/CRITICALITY
specification
(Exactness of

dimension/specification,

High, Medium, Low
criticality……

SPEED (50% over estimated
time…- (1point) 50%

time
save over estimated…

+
(1point)…

METHOD (Economical; use

Of tools; Safety and

Hygiene,
Initiative)…………………
…..

TOTAL POINTS
(T)………

(T/4)
GRADE…………….

REMARKS: Approximate working time is BY:
Four (4) hours

________________________________
________________________________

__________________________
__________________________

Designation

GRADE ………………………………

192

OPERATION TITLE: Boring

Purpose: Operation of enlarging a hole previously made by drilling.

Condition or Situations for the Operation

Boring is the operation of enlarging a hole previously made by drilling, casting, or
some other means. The operation is done with the use of a single point toll held in a
boring tool holder. Holes are bored to make them accurate in size and concentric with
the outside surface.

Consequently a hole which has been drilled and reamed may be cylindrical,
parallel and accurate to size. But is can not be guaranteed that its center line will be true
with the rotational axis of the work for reasons that the drill may have run out a little and
the reamer would have followed the drilled hole. It may be suggested that when boring
holes the size should be finished by reaming.

TOOLS, EQUIPMENT AND
1. Tools

1.1 Boring tool with holder
1.2 Vernier caliper
1.3 Inside caliper
1.4 T-wrench
1.5 Socket wrench
1.6 Open end wrench
1.7 Safety goggles
1.8 Steel rule
1.9 Scriber
2. Materials
2.1 68Ø x 34 CRS
2.2 MS Drawing No. 108
3. Equipment
3.1 Pedestal grinder
3.2 Lathe machine

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Figure 1. Boring Tool With Bits and Holder

Rules for Boring Holes
1. Use the largest diameter boring bar that will fit into the hole and hold it as

short as possible.
2. Take light cuts together with the right amount of feed. This will help to reduce
chatter and give a finish on the surface of the hole.
3. Grind the cutting tool to the correct shape. The amount of radius at the cutting
edge is an important factor to achieve good finish.

Task No. 1 – Boring the Hole of the Marking Gauge Flange
1.1 Secure the workpiece, complete tools and materials form the tool keeper or
instructor
- Replace damage tools with good ones
1.2 Study the blueprint of the marking gauge flange (Figure 2) and not down
specification.

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Figure 2. Blueprint of the marking Ganges Flange
1.3 Clamp the workpiece in the chuck

- Use minimum overhang

Figure 3. Mounting the Workpiece In a Chuck

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1.4 Select and set-up the boring tool

a. Choose the boring tool/bar or sufficient length to cover the full depth of the
hole
- Be sure that the tool point protrudes at the end of the bar

b. Clamp the tool with sufficient overhang to cut through the hole as required

Figure 4. The Tool is clamped with minimum Overhang
c. Set the tool to 0.1 – 0.3mm above the center.

- The tool is usually set at that angle that its shank will permit among
tolerance when boring the hole

Figure 5. Correct Set-Up of the Boring Tool

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d. Check the set-up by moving the tool into the hole.

Figure 6. A Method of Checking the Set-up of the Tool

1.5 Set the spindle speed and feed
a. Select speed and feed with lathe controls
- Read possible values on the machine data plate

CALL INSTRUCTOR TO CHECK THE WORK

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1.6 Take a trial cut using automatic feed
a. Position the point of the tool just within the hole
b. Wind the cross-slide until the point of the tool just touches
the surface of the hole,

Figure 7. Positioning the Tool For Setting-Up Depth of Cut
c. Zero the cross-slide collar and move out the tool from the hole
d. Set the cross-slide scale to about 0.3mm. figure 8.

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Figure 8. Setting The Scale for a Trial Cut

e. Star the spindle, engage the feed and take a trial cut about
.4mm long, Figure 9

Figure 9. Taking a Trial cut

f. Stop the spindle and withdraw the tool and bring it to clear position
g. Check diameter with a vernier caliper or an inside caliper

1.7 Rough turn the hole using automatic feed
a. Set the depth of cut using the cross-slide scale
- Leave enough materials for the finish cut
b. Mark a line on the bar at the same length as the depth of
hole, Figure 10 using steel rule and a piece of chalk

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Figure 10 Marking out the depth

- The marked line will serve as the gauge to ensure that the
depth of a hole will not be over the requirement.

C. Start the spindle, engage the feed and take cuts,
-If the amount of material to be removed is big, take several
rough cuts
-Disengage the feed when the marked line nears the face of
the hole
-Apply coolant

Figure 11. Taking a Rough Cut
d. Stop the spindle, move cut the tool form the hole and bring in

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to clear position
e. Check the diameter and depth of hole with a vernier caliper
1.8 Bore the hole to specification
a. Disengage the feed when the marked line leaves the face of the

workpiece.
b. Check if the required surface finish is attached
c. Stop the spindle, move out the tool from the hole and bring at

clear position
d. Check the diameter and depth of hole with a vernier caliper

1.9 Face bottom of the hole to depth
a. Set the tool until marked line is almost aligned to the face of
workpiece

Figure 12. the Tool Is Set-Up To Face Bottom of Hole

b. Start the spindle and face bottom until specified depth is attained
c. Stop the spindle, move out the tool form the hole and bring at

clear position
d. Check the depth with a vernier caliper