Turning workpiece

251

b. Clamp the tap in the attachment and tighten

Figure 17. Mounting The Tap in the Tapping Attachment
c. Set friction device for thread size

Figure 18. Adjusting The Attachment Thread Size

2.6 Tap the hole

a. Bring the tailstock forward so that the tap is close to the hole

Figure 19. Setting-Up the Tap Into The Hole

252

b. Clamp the tailstock

POSITION GUARD WEAR SAFETY GOGGLERS

c. Start the spindle
d. Arrange the flow of cutting oil into the hole
e. Feed the tap forward using the tailstock spindle

Figure 20. Tapping The Hole
f. Stop and reversed the spindle when the thread is cut

- Be sure that the spindle is stopped and reverse before the tap is
Disengage from the thread
g. Wind the tailstock spindle back to remove the tap as when it enters
the hole\
h. Stop the spindle

2.7 Check thread
a. Clean the hole with a spring cleaner
b. Check the thread with a screw plug gage

Figure 21. Using A Screw Plug Gage To Check A Tapped Hole

253

Precaution

IMPORTANCE

1. Clean the tools and machine before and after using.
2. Place tools inside the tool box when not in use.
3. Maintain correct oil levels of machine parts and gear mechanisms.
4. Always make sure that part are tightly connected or bolted.

254

TEST REVIEW EXECRCISES

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

_________ 1. The process of cutting threads on the surface of a hole using a tap
is called
a. screw cutting
b. reaming
c. tapping
d. boring

__________2. The tool used in tapping a hole is called
a. reamer
b. twist drill
c. screw pitch gage
d. tap

__________3. Hand tapping is performed on the lathe to tap
a. blind holes
b. through holes
c. tapered holes
d. recessed holes

__________4. Machine tapping is performed on the lathe
a. tap
b. through holes
c. blind holes
d. recessed holes

__________5. To perform machine tapping the tap is held in
a. t-tap wrench
b. adjustable tap wrench
c. tapping Attachment
d. drill chuck

255

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 FACTORS Rati
REQUIREMENT ng
Give the blueprint of the workpiece, complete tools and A. Quality/Appearance
materials the trainee must be able to: (symmetry; Verticality;
Horizontality ;
1. Tap a blind hole Workmanship,
Finish)………….
2. Tap a through hole B. Accuracy/Criticality
(Exactness of
dimension/specification,
High, Medium, Low
criticality
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

256
Operation Title: Turn a taper with compound rest
Purpose: To produce taper workpiece
Condition or situation for the operation:

Compound rest is used to turn short taper.
The compound rest base can be swiveled to any desired angle.
I. Equipment and materials
A. Right-hand turning tool
B. Facing tool
C. Steel rule, 6”
D. Lathe with chuck
E. Quick-change tool post and toolholder
E. Wrenches for chuck, tool post, toolholder, and compound
F. Cutting oil
G. Hex steel bar, SAE 1018, 11/8” diameter, $ 1/*” long

(NOTE: An 11/8” round steel bar may be substituted.)
I. Clean shop clothe
II. Procedure
A. Check oil levels and perform daily maintenance
B. Chuck work with about 2” protruding from end of chuck jaw
C. Face end smooth
D. Set speed at 425 rpm
E. Loosen compound rest lock nuts and set compound at a 25 digress angle

to axis of work (Figure 122)

257
(CAUTION: When cutting angles [tapers] with the compound, it is

recommended to cut toward chuck; this keeps your hand away from
revolving chuck.)

(NOTE: Depending on the zero reference of the protractor base the
compound, the reading will be 25 or 65)
FIGURE 122

F. Set tool to center height
G. Position tool so that only the point makes contact with work

when tool is fed along the angular setting of compound; place
tool near end of work
(Figures 123 and 124)

258

FIGURE 123 FIGURE 124

H. Lock tool post and tool holder in place

G. Turn on lathe and start spindle

J. Apply cutting oil as required during cutting; advance tool 0.150” with the
cross feed; feed tool into work, using compound hand wheel with a slow,
continuous motion until tool stops cutting

K. Crank tool back with same motion until it clears work

(NOTE: Turning the compound with both hands in a continuous motion
gives a smooth finish without feed marks because there is pressure on
tool at all times.)

259
L. Continue this process until the work comes to a point (Figure 125)

FIGURE 125

M. Clean machine and put away all tools
N. Complete evaluation sheet on following page
O. Turn in work and evaluation sheet to instructor

260
NAME________________________________________ SCORE _____________

In Out of
Tolerance Tolerance

Measurement of angle 25digrees + 30
-

Measurement of overall length 4 1/16” + 1/32
- 0.0

Finish of machined surface, # 32

Remarks _________________________________________________________
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________
______

261

EVIDENCE PLAN

Course: Machinist NC-1

Unit of Competency: Turn Workpiece

Module Title: Turning Workpiece

Ways in which evidence will be collected Question/Interview
(Tick the column) Demonstration
Observation
The evidence must show that the Third party Report
candidate…… Portfolio

1. Interpret plan/ working drawing XX

2. Select work holding devices XX

3. Identify cutting tools XX

4. Check coolant level X

5. Mount and center workpiece XX

6. Perform set up operation XX

7. Set up workpiece XXX

8. Use tools and equipment to mount workpiece XX

9. Calculate speed and feed XX

10. Use appropriate lathe accessories XXX

11. Observe safety procedures XX

12. Check workpiece measurement XX

13. Perform safe handling of tools XX

14. Use personal protective devices XX

Prepared by: Ninfa E. Subibi Date: October 26,2003
Checked by: Date:

ANDSWER KEYS: 262
ALPHABET OF LINES: 2
1.) CENTER LINE

2.) DIMENSION LINE
3.) VISIBLE LINE

263

6.) INVISIBLE LINE ----------------------------

7.) SECTION LINE

8.) LONG BREAK LINE

9.) BORDER LINE

1O.) SHORT BREAK LINE

MODEL ANSWER: LATHE MACHINE
1. C
2. C
3. A
4. B
5. C

MODEL ANSWER :SAFETY DEVICES AND PRECAUTIONS IN THE USE OF LATHE
1. a. flying chips
2. c. vertical & adjustable guard
3. d. metal hook
4. b. cuts on fore-arm
5. e. safety goggles

MODEL ANSWER : Turning Safety Rules
1. false
2. false
3. false

264

4. true
5. true
6. true
7. false
8. false
9. false
10. true

SELF-CHECK: MOUNTING WORK BETWEEN CENTERS
1. C
2. A
3. C
4. A
5. A

MODEL ANSWER: R P M CALCULATION
1. B
2. A
3. B
4. A
5. C

MODEL ANSWER: RECOGNIZING EFFECT OF HEAT

1. B. Expand when heated, contracts when cooled
2. A. Temperature
3. c. 0.0000106

MODEL ANSWER:

1. C – SOLUBLE OIL
2. D – FACILITATE PRODUCTION, CLEANING HEATING
3. B. DECREASED
4. MINERAL OIL AND LARD

OPERATION SHEET NO.1

MODEL ANSWER: CENTERING
1. C. – CENTERING
2. D. – SURFACE GAGE
3. A. – DIAL INDICATOR
4. 4. – CHALK
5. C. – SHIM
6. A. – CIRCLE AND CENTERPOINT
7. A. – JAW
8. B. – CORNERS
9. B. – ALTERNATIVELY
10. B. – NO DEFLECTION

265

MODEL ANSWER: FACING

1.C-FACING
2.A-STEP TURNING
3.A-FACEPLATE
4.B-CENTER TO OUTSIDE
5.A-CROSSLIDE

MODEL ANSWER: TURNING STRAIGHT DIAMETERS

1. A – INTERNAL RECESS
2. D – BORING
3. C – SPECIAL FITTING OF PARTS

MODEL ANSWER: SHOULDER TURNING

1. D – SHOULDER TURNING
2. B – FILLETED
3. B- SQUARE
4. B – FORM
5. B - HERMAPHRODITE

MODEL ANSWER: RECESSING

1. B
2. A
3. C

MODEL ANSWER: DRILLING

1. C- DRILLING
2. B-COMBINATION
3. A-DRILL HOLDER FASTENED TO THE TOOL POST
4. D-NUMBERS
5. A-BEARING SURFACES FOR LATHE CENTERS

MODEL ANSWER: BORING

1. B – BORING
2. B – BORING TOOL
3. A – TAKING RIGHT CUTS WITH THE RIGHT AMOUNT OF FEED
4. C – GRINDING THE TOOL TO THE CORRECT SHAPE WITH ENOUGH SIDE RADIUS

AT THE CUTTINGTOOL
5. C – 0.1 TO 0.3

MODEL ANSWER: RECESSING

1. B – REAMING
2. A – FLUTED REAMER
3. B – STEEL REAMERS

266

MODEL ANSWER: THREAD AND THREADINGS

1. D
2. C
3. B
4. C
5. B

MODEL ANSWER: PARTING OFF

1. B
2. B
3. A

MODEL ANSWER: TAPPING

1. C
2. D
3. B
4. B
5. C

267

CBLM FORM B:

LEARNER’S DIARY

DATE JOBS UNDERTAKEN AND OTHER WORKPLACE EVENTS

268

CBLM FORM C:

RECORD OF ACHIEVEMENT

DATE ACTIVITY INSTRUCTOR INSTRUCTOR
(WRITE HERE YOUR ACTIVITY REMARKS SIGNATURE

FOR THE DAY)

269

OPERATION TITLE: TURNING WORKPIECE

PURPOSE: Turning operation is necessary in order to produce a component.

CONDITION:
Given a blueprint, tools, and materials the trainee should be able to turn

workpiece in one hour.

EQUIPMENT: Lathe machine

PROCEDURE:

13. Mount the work in the lathe.
14. Obtain or prepare a sharp cutting tool of the shape & size needed.
15. Insert the tool in the holder, with the point projecting about 13 mm (1/2”).
16. For turning steel or cast iron, set the tool holder in the tool post so that the point of

the tool is between 0o and 5o above the center of the workpiece. Position the tool
holder so that it raised project only slightly beyond the edge of the compound rest.
17. Saving the tool holder so that the cutting edge of the tool ids more than 90o
preferably 8ofrom the surface of the workpiece.
18. With the cross-feed crank, withdraw the tool until its clear the work. Start the lathe
and carefully advance the tool until it just touches the work. If possible set the
micrometer collar on the cross feed screw at zero. Advance the tool to desire cuts.
19. Set the rate and direction of feed desire. Advance the tool to the end of the
workpiece with the carriage hand wheel, and engaged automatic feed.
20. When about 6.35 mm (1/4”) of the piece has been machine, disengage the power
feed, stop the machine and move the tool back to the end of the workpiece with
the carriage hand wheel. Test the piece for size with a micrometer.
21. If the piece is under size or oversize make necessary adjustment. Be sure to allow
about 0.25-0.76 mm (0.010”-0.030”) for the finish cut.
22. After making adjustment, proceed the rough cuts using a feed rate of about 0.13-
0.25 mm (0.005”-0.0010”) per revolution.
23. Continue until the tool or the side of the compound rest is within about 6.35 mm
(1/4”0 of the dog. Stop the lathe and run the carriage back until the point of the
tool is past the end of the workpiece.
24. If the entire length of the workpiece must be machined, remove the piece from the
dog, and place the turned end. Again mount the workpiece in the lathe and proced
turning.

270