ATM-412 Machining M6 - Miss Hanna's Classroom...

Machining

Module 6: Lathe Setup and Operations

(Part 2)

PREPARED BY

Curriculum Development Unit

August 2013

© Applied Technology High Schools, 2013

ATM 412 – Machining

2 Module 6: Lathe Setup and Operations (Part 2)

Module 6: Lathe Setup and Operations (Part 2)

Module Objectives Upon the successful completion of this module, the student will be able to:

Describe the parallel turning operation.

Operate the lathe safely to perform parallel turning.

Describe the taper turning operation.

Operate the lathe safely to perform taper turning.

Describe the grooving operation.

Operate the lathe safely to perform grooving operation.

Describe the threading operation.

Operate the lathe safely to perform threading operation.

Describe the drilling operation.

Operate the lathe safely to perform drilling operation.

Describe the polishing operation.

Operate the lathe safely to perform polishing

Describe boring, parting off, knurling, and grinding operations.

Module Contents

Topic Page No. 1 Parallel Turning 3

2 Taper Turning 10

3 Grooving 17

4 Threading 21

5 Drilling 30

6 Polishing 33

7 Other machining operations 35

References 36



Lathe Operations

1. Parallel (Straight) Turning

Parallel turning is to move the cutting tool parallel to the longitudinal axis of

the workpiece in order to reduce its diameter. (This axis is called Z axis).

Fig. 6.1 shows parallel turning operation and turning cutting tool.

Fig. 6.1: Parallel Turning

1.1 Rough Turning

Rough turning is used to remove most of the excess material as quickly as

possible and to true the work diameter.

The roughing cut should be taken up to (0.8 – 1.3 mm) more than the

required diameter of the workpiece.

1.2 Finishing Turning

The purpose of finish turning is to bring the workpiece to the required

size and to produce a good surface finish. Generally only one finish cut

is required since no more than 0.8 – 1.3 mm should be left on the

diameter for the finish cut, but regarding OPTIMUM lathe which we

have in our workshops and due to its size, the finishing cut

should not be more than 0.5 mm.



1.3 Practical Task 3: Parallel Turning (Rough and Finishing cuts)

To do parallel turning to a diameter 12 mm and length = 18 mm

Before turning (blank part dimensions: Ф 25 X 78 mm): See Fig. 6.2 a.

After turning: See Fig. 6.2 b.

“In certain cases the available Aluminum or Teflon rods in the market are 25.4 mm

in diameter, this extra 0.4 mm should be considered and removed. See Fig. 6.3.”

Material: Aluminum / No soluble cutting oil is required

Fig. 6.2. a: Before parallel Turning

Fig. 6.2 b: After Parallel Turning

Fig. 6.3: available Aluminum rod in the market.



1. Read, and follow all the safety regulations mentioned previously.

As always, wear safety glasses and keep your face well away from the work

since this operation will throw off hot chips and/or sharp spirals of metal.

Make sure the half nut lever is disengaged and the carriage’s lock is not

tightened down.

2. Mount the work securely in a three

jaw universal chuck, with no more

than three times the diameter

extending beyond the chuck jaws.

Fig. 6.4.

20 mm chucking depth is suitable.

(Chucking depth is the length of the

part that inserted inside the chuck).

The center hole that previously drilled

in practical task 2 could be used to

help in accurately centering the

workpiece by using the tailstock (Fig

6.5). Since this workpiece is not too

long so the tailstock is not necessary

to be used to support the workpiece

during cutting operations, however, it

will be used to initially center it.

Fig. 6.4

Fig. 6.5: Workpiece is supported by

a center held on the tailstock

3. Move the tool post to the left of the

compound rest and grip the tool

holder short. Fig. 6.6.

(On some machines the tool post is

permanently fixed on the left side of

the compound rest).



4. Fasten the turning cutting tool in the

tool holder, and set the point to the

center as shown in Fig. 6.6. The

cutting tool could be set

perpendicular to the axis of the

machine or slightly to the right to

provide a clearance between the

cutting tool and the workpiece. The

relative position of the cutting tool to

the workpiece is shown in Fig. 6.7.

The cutting speed is set within a

range of (400 – 750 RPM).

The feed rate should be within a

range (0.1–0.2) mm/rev. For

OPTIMUM lathe machine use the

default gearing arrangement i.e. feed

rate = 0.1 mm/rev.

Fig. 6.6: Cutting tool is set to the center

Fig. 6.7: Turning tool and its position relative to the workpiece

5. Move the carriage towards the chuck.

Use a vernier caliper as shown in

Fig.6.8 and move the carriage to

exactly locate the tip of the sharp tool

to the required length (18 mm),

remove the vernier caliper and then

rotate the chuck by hand. Start the

machine, then use the cross slide to

scratch a line to show the end of

turning. Stop the machine and move

the cross slide back away from the

workpiece.

Fig. 6.8: Measure the required cutting length



6. Move the carriage until the tip of the

tool is close to the free end of the

work piece, then advance the cross

slide until the tip of the tool just

touches the surface of the workpiece.

(Fig. 6.9 a). Hold the cross slide

handle and adjust the micrometer

collar to zero (Fig. 6.9 b).

Fig. 6.9 a: The cutting tool touches the outside surface of the workpiece

Fig. 6.9 b: Micrometer collar is adjusted to zero

Fig. 6.10: Start position for turning

7. Move the carriage to the right until the

tip of the tool is just beyond the free

end of the work.

Rotate the cross slide handwheel until

the collar moves a distance = 1 mm

(i.e. the diameter will be reduced by 1

mm).

This is the start position for turning as

shown in Fig. 6.10



Engage the knob to select the carriage

automatic feed as shown in Fig. 6.11,

and check the direction of movement

to be toward the headstock.

Rotate the chuck by hand.

Start the machine, and then engage

the automatic feed lever.

Fig. 6.11: Select the carriage automatic feed

8. Take a light trial cut at the end of the

work (approximately 5 mm length),

and then disengage the automatic

lever, stop the machine but do not

move the cross feed handle setting or

the graduated collar. Move the

carriage away from the chuck as

much as possible to have enough safe

space to measure the diameter as

shown in Fig. 6.12.

Fig. 6.12: Diameter measurement

If the dimension is correct, return the carriage back, near the workpiece free

end, start the machine again and use the automatic feed lever until you reach

to the line scribed at step 5, and then stop the machine.

9.

10.

Move the carriage back to the start position, in front of the free end of the

work. Rotate the cross slide handwheel clockwise to feed the new cutting

depth as mentioned in step 7. Start the machine and engage the carriage

automatic feed lever. Stop the automatic movement at the end of turning

exactly as mentioned in step 8, and then stop the machine.

Accordingly, calculate the rest of the material required to be removed to

make the diameter 18.5 mm (Rough cuts). Repeat step 9. Until you reach a



11.

12.

13.

diameter = 18.5 mm (0.5 mm over size in diameter will be cut by a finishing

cut). Stop the machine.

Adjust the speed to (range of 800 – 1100 rpm) for finishing. Adjust the feed

to (0.1 – 0.2 mm/rev) for finishing. Adjust the cross slide graduated collar to

= 0.5 mm depth of cut (i.e the diameter will be reduced by 0.5 mm). Start

the machine and engage the automatic feed.

Take a light trial cut at the end of the workpiece, (approximately 5 mm

length) then stop the machine and check the diameter for exactly 12 mm. If

the diameter is correct, then start the machine and continue to a length = 18

mm. Stop the machine.

Fig. 6.13 a: checking length Fig. 6.13 b: checking diameter

Move the carriage back near the tailstock. Measure the diameter and length

of the turned part. If the length need to be adjusted, move the carriage back

to the last point on the turned part, then use a digital vernier caliper to

exactly mount the cutting tool at 18 mm. then start the machine and move

the cross slide backward and forward to straighten the shoulder of the turned

part.

Move the carriage back near the tailstock. Stop the machine and remove the

work.



2. Taper Turning

Taper turning is the process used to increase or decrease the diameter of

the workpiece in a uniform rate. (Fig. 6.14).

Fig. 6.14: Taper Turning

Taper turning can be done by different ways but the most common methods

are:

1) Offsetting the tailstock, there by setting the lathe centers out of

alignment. This is mainly used for long tapers. Fig. 6.15 shows

tailstock offset method.

Fig. 6.15: Tailstock offset method

2) Setting the compound rest at the required angle. This method is

applied for short tapers.



2.1 Calculating the angle:

The angle at which the compound rest is set is computed in the

following manner:

a) If the angle with the center line of work is given, the compound

rest is set to that angle.

b) If the included angle is given, the compound rest is set to one-half

the given angle. Fig. 6.16

Fig. 6.16: Included angle of a taper

c) If the diameters at the ends of the taper and the length of the

taper are given, the angle for the compound rest setting is

computed as follows: Fig. 6.17

Fig. 6.17: angle of the taper

= 0.625



2.2 Practical Task 5: Taper Turning To cut a taper according given dimensions. Before taper turning: See Fig. 6.18

After taper turning: See. Fig. 6.19

Material: Aluminum / No cutting oil is required

Fig. 6.18: Before taper turning

Fig. 6.19: After taper turning

1. Read, understand fully and follow all the safety regulations mentioned

previously.

As always, wear safety glasses and keep your face well away from the

work since this operation will throw off hot chips and/or sharp spirals

of metal.

Make sure the half nut lever is disengaged and the carriage’s lock is

not tightened down.

2. Mount the work in a three jaw chuck.



3. Calculate the length of the taper as shown in Fig. 6.20

Fig. 6.20

tan 200 = 0 .364

tan 200 = (25-12)/2L

L=13/2x0.364

= 17.85 mm



4. Pivot the compound rest to the

desired angle, (20°) as shown and

lock it in position. Fig. 6.21

Set the cutting tool to the exact

center of the machine. With the

cutting tool set as for turning, (a tool

holder that will provide ample

clearance should be selected).

Fig. 6.21: Compound rest is set to 20°

5.

6.

7.

Move the carriage toward the chuck,

out of the workpiece until a point

near the end of the taper required.

Fig. 6.22

Use the Vernier caliper or steel rule

and move the carriage to exactly

locate the tip of a sharp tool to the

required length (End of the taper at

17.85 mm).

Fig. 6.22: The cutting tool in correct position to scratch a line at the end of the taper

Rotate the chuck by hand. Start the

machine at range of (500 – 800

RPM). Use the cross slide to scratch

a line to show the end of the taper.

Fig. 6.23

Stop and move the cross slide back

away from the workpiece.

The usual practice is to turn a taper

from smaller diameter to the larger

diameter.

Fig. 6.23: light mark is

scratched on the surface to show the end of the taper



8. Move the carriage back to bring

the cutting tool bit into the starting

position with the work, i.e. just touch

the diameter 25 mm at its start point

as shown on the drawing and

indicated by the circle and arrow.

Fig. 6.24

Fig. 6.24: The position of the

toolbit at starting point

Make sure that the compound rest is

not all the way at the end of its

travel towards the chuck. Adjust the

cross slide collar to zero. Rotate the

cross slide a distance = 1 mm. Fig.

6.25. and then start the machine.

Fig. 6.25: The tool is ready to cut the taper



9.

10.

11.

Advance the tool by the compound

rest handle to remove material at the

pivoted angle. The cutting tool

should be advanced until it is clear

from the workpiece. Fig. 6.26

The entire cut must be made without

stopping the cutting tool.

Reverse the compound rest

movement to bring the tool back to it

is start position, then use cross slide

movement to add a new depth of

cut. Fig. 6.27

Fig. 6.26: Cutting the taper

Fig. 6.27: The compound rest is reversed back after each cut

Repeat steps 7 to 10 until a total of 6.5 mm depth of cut is achieved

(i.e reach the surface of 12 mm diameter). If the calculations are

correct, the taper will end at the mark that you made at step 6. (at

length = 35.85 mm Fig. 6.28). Stop the machine and then remove the

workpiece.

Fig. 6.28: work length after taper turning



3. Grooving (Recessing):

Grooving is often referred to as recessing, undercutting, or necking. It is

the process of cutting a groove (generally square, round and v-shaped) to

specific depth and width. Fig. 6.29

Fig. 6.29: Grooving Process

Groove can be cut outside a workpiece as in (Fig. 6.30) or inside an existing

hole as in Fig. (6.31)

Fig. 6.30: External grooving Fig. 6.31: Internal grooving



3.1 Practical Task 6: External Grooving To cut an external groove to a given dimensions:

Before grooving: See Fig.6.32.

After grooving: See Fig. 6.33.

Material: Aluminum /No soluble cutting oil is required

Fig. 6.32: Before Grooving

Fig. 6.33: After Grooving

1. Read, understand fully and follow all the safety regulations

mentioned previously.

As always, wear safety glasses and keep your face well away from

the work since this operation will throw off hot chips and/or sharp

spirals of metal.

Make sure the half nut lever is disengaged and the carriage’s lock is

not tightened down.

2. Set the lathe to one-half the

turning speed, (about 350 -500

RPM).



3. 4.

Hold the work in a 3-jaw chuck. Mount the proper-shaped tool bit

in the tool holder. See Fig. 6.34.

The width of the tool bit is 3 mm

as per the groove width.

Fig. 6.34: grooving tool

Fig. 6.35: Groove position on

the drawing

Fig. 6.36: Tool is located in the correct position for cutting

Fig. 6.37: Cutting the groove

5.

6.

7.

8.

Set the cutting tool to center and

at 90° to the work.

Lay out the location of the groove,

using a vernier caliper. Locate the

tool bit on the work at the position

where the groove is to be cut.

The right edge of the tool must be

at a length = 15 mm from the

right side of the work. Fig. 6.35

and Fig. 6.36

Start the lathe and use the cross

slide handle to feed the cutting

tool towards the work until the

toolbit lightly marks the work.

Hold the cross slide handle in

position and then set the

graduated collar to zero. Calculate

how far the cross slide screw must

be turned to cut the groove to the

proper depth (12-10 =2) i.e the



9.

10.

11.

depth = 2/2 = 1 mm

Note: the graduated collar should

be rotated one complete turn in

order to reduce the diameter by

2mm.

Groove the work to the proper

depth at a steady feed rate. Fig.

6.37. It is desirable to move the

carriage by hand a little to the

right and left while grooving to

overcome chatter (if and only if,

the recess width is wider than the

cutting too bit width).

Stop the lathe and check the depth

of the groove with outside calipers

or a knife-edge vernier caliper.

Remove the workpiece shown in

Fig. 6.38

Fig. 6.38: After Grooving



4. Threading

A thread may be defined as a helical or spiral ridge of uniform section

formed inside or outside a cylinder or cone shape. Threading operation is

shown in fig. 6.39

Fig. 6.39: Threading operation

The outside thread is also called external thread. A screw thread is an example of external thread. Fig. 6.40 The inside thread is called internal thread. A nut is an example of internal thread. Fig. 6.41

Fig. 6.40: External Thread Fig. 6.41: Internal thread

Threads also could be classified as left hand and right hand threads:

Right-hand thread: Right-hand thread is a type of threaded section onto which a nut is threaded (to be tightened) in a clockwise direction.

Left-hand thread: A left-hand thread is a type of threaded section onto which a nut is threaded (to be tightened) in a counter clockwise direction.



4.1 Threads are used for several purposes:

1. To fasten devices such as screws, bolts and nuts, Fig. 6.42

Fig. 6.42: bolts and nuts are used to fasten two parts together

2. To provide accurate measurement, as in a micrometer.

3. To transmit motion; the threaded lead screw on the lathe causes the

carriage to move along.

4. To increase force; heavy load can be raised with a screw jack. Fig.

6.43

Fig. 6.43: A screw jack; threads are used to increase force

Because the wide range of applications. Threads are designed in different

forms as shown below:

Fig. 6.44 Metric threads Fig. 6.45: American Acme thread Note: Tables are available in machining handbooks for the standard forms and their respective specifications, such as pitch, thread angle, depth of cut … etc, according to the thread diameter.



4.2 Thread Terminology:

Fig. 6.46: Thread Terminology

The major diameter is the largest diameter of an external or internal thread. The minor diameter is the smallest diameter of an external or internal thread. The pitch diameter is the diameter of an imaginary cylinder that passes through the thread at a point where the groove and thread widths are equal. . The pitch (P) is the distance from a point on one thread to a corresponding point on the next thread, measured parallel to the axis. Pitch is expressed in millimeters for metric threads. The angle of thread is the included angle between the sides of a thread measured in an axial plane.

The lead is the distance a nut advances lengthwise in one complete revolution.

The metric threads are identified by the letter M, the diameter, and the pitch. For example, a metric thread with an outside diameter of 5 mm and a pitch of 0.8 mm would be identified as follows: M 5 x 0.8. The angle for international metric threads is 60° and the depth of cut is equal = 0.6134 x Pitch. The imperial system threads are identified by “The number of threads/inch”.



4.3 Parts used in thread cutting:

The thread cutting on the lathe machine could be done by using the following parts and tools:

1. Quick change gear box is used to select the required pitch on the

machine but in the OPTIMUM lathe machine there is no quick

change gear box, so you will use the gearing arrangement to select

the required pitch on the machine as shown in Fig. 6.47.

Fig. 6.47: Available threading pitches and gearing arrangement.

2. Center gauge: used to set the threading tool on center with the tool

axis at 90° to the centerline of the work. Fig. 6.48

Fig. 6.48: Center gauge



3. Screw pitch gauge: Is used to check the thread pitch that being cut

on a workpiece. See Fig. 6.49

.

Fig. 6.49: Screw pitch gauge



4.4 Practical Task 7: Threading

To cut the thread shown in Fig.6.51 according to the following specifications:

Metric thread

M 12 X 0.75

Diameter

12

Pitch

0.75

Depth

0.406

Thread included angle

60°

Note: The specifications of each thread are provided in machining handbooks.

Before threading: See Fig. 6.50.

After threading: See Fig. 6.51.

Material: Aluminum / No soluble oil is required.

Fig.6.50: Before Threading

Fig. 6.51: After Threading


previously. As always, wear safety glasses.

2. Check the major diameter of the work for size. 12 mm.

3. Set the rotational speed to 1/4th the speed used for turning i.e around 175 –

250 rpm.



Use the threading pitch table shown in Fig.6.52 to select the desired pitch.

Fig.6.52: threading pitch table.

4.

5.

6.

Select the gearing arrangement in the

Fig.6.53 to cut 0.75 pitch.

The tool height can be set by using the

centerline scribed on the tailstock spindle

or with the center point.

Mark the length to be threaded by cutting

a light groove at this point with the

threading tool while the lathe is

revolving.

Fig. 6.53: Set the gearbox to the required pitch



7.

8.

9. 10. 11. 12. 13.

Move the carriage until the point of the

threading tool is close to the right end of

the work.

Turn the crossfeed handle until the

threading tool is close to the diameter.

Stop turning the crossfeed when the

handle is at the 3 o’clock position

(Fig.6.54). (This will help in making an

easier threading operation).

Hold the crossfeed handle in this position

and set the graduated collar to zero (0).

Turn the compound rest handle until the

threading tool lightly marks the work.

Move the carriage to the right until the

cutting tool clears the end of the work

Feed the compound rest clockwise about

0.1 mm.

Engage the split-nut lever (Fig. 6.55),

and take a trial cut along the length to be

threaded. At the end of the cut, turn the

crossfeed handle counterclockwise to

move the cutting tool away from the

work but do not disengage the split nut.

Reverse the spindle rotation until the

cutting tool has just cleared the start of

the threaded section.

Stop the lathe and check the pitch with a

metric screw pitch gage, rule, (Fig. 6.56).

Fig. 6.54: Crossfeed handle at 3 o’clock position

Fig. 6.55: Split-nut lever



14. 15.

If the pitch produced by the trial cut is

not correct, recheck the gearing

arrangement selected.

Take successive cuts by repeating the

above cutting steps four times (cutting

depth of 0.1 mm for each cut) until you

reach to the required depth of cut 0.406

mm≈0.4 mm. Set the depth of all

threading cuts with the compound rest

handle.

Note:

Never disengage the split nut until the

thread has been cut to the final depth.

Remove the burrs from the top of the

thread with a file. Fig. 6.57

Fig. 6.56: Screw pitch gauge

Fig. 6.57: Remove sharp edges



5. Drilling

Drilling is to make a hole having a specific diameter and depth in a solid material. The

cutting tool mounted in a drill chuck on the tailstock and forwarded into the

revolving workpiece along the Z axis. Fig. 6.58.

A center drill must be used before drilling to spot a center hole as a guide for the

twist drill.

If a relatively large hole is to be drilled, a small lead hole is drilled first. This hole,

will reduce the feeding pressure required for the large size drill.

In technical drawing, the hole is shown as hidden lines to indicate the diameter and

length of the hole as shown in fig. 6.59

The speed of drilling is calculated in the same way that explained in module 3 but

the diameter used for calculations is the diameter of the hole.

Fig. 6.58: Drilling operation

Fig. 6.59: Drilling as shown in technical drawing



5.1 Practical Task 8: Drilling

To drill a hole in the center according to the drawing

Finished part: As shown on the drawing. Fig.6.61

Material: Aluminum / No soluble oil is required

Fig. 6.60: Before drilling

Fig. 6.61: Finished part


previously.As always, wear safety glasses and keep your face well away

from the work since this operation will throw off hot chips and/or sharp

spirals of metal.

2.

Mount the workpiece in a three

jaw chuck.

Fig. 6.62: drill is mounted in a drill

chuck

3 Mount the correct size drill, (6

mm drill) in a drill chuck,

mounted on the tailstock spindle.

Fig. 6.62



Fig. 6.63: Tailstock is locked in position

4.

Set the rotational speed to

around 800 RPM.

5. 6. 7.

Release the tailstock lock and

advance the tailstock until it

reaches near the workpiece and in

front of the work free end. Lock

the tailstock at this position. Fig.

6.63

Rotate the chuck by hand

Start the machine

8.

Advance the tailstock spindle by

rotating the handwheel clockwise

to feed the tool into the work at

slow and steady feed rate. Fig.

6.64.

When the conical shape (head of

the tool) is totally fed into the

workpiece, stop tool movement

and consider this point as your

zero point, then adjust the

tailstock micrometer collar to

zero, this will enable you to know

the exact distance that you will

move into the workpiece.

Alternatively the tailstock has a

built in rule on its collar which

could be used for the same

purpose. Fig. 6.65

Fig. 6.64: Feed the tool using tailstock handwheel

Fig. 6.65: measuring rule on the

tailstock collar



9. Resume feeding the cutting tool

until you make 15 mm deep hole.

Fig. 6.66: checking the depth of the hole

10. Reverse the tailstock handwheel

and stop the machine.

11.

12.

Release the lock of the tailstock

and draw it back to its position on

the right side of the machine.

Use the Vernier caliper to check

the depth of the hole as shown.

Fig. 6.66.

6. Polishing

Polishing is a finishing operation performed on the workpiece to improve the

surface finish. Abrasive cloth (sand paper) is used. The finish obtained is

directly related to the coarseness of the abrasive cloth used.

A fine-grit abrasive cloth produces the best surface finish. Aluminum oxide

abrasive cloth should be used for polishing most ferrous metals, while

silicon carbide abrasive cloth is used on nonferrous metals. Fig. 6.67

Fig. 6.67: Polishing



6.1 Practical Task 9: Polishing: To polish the surface of the machined part:

1. 2.

Read, understand fully and follow all the safety regulations mentioned

previously.

As always, wear safety glasses.

Be sure that all loose clothing is tucked in to prevent it from becoming

caught by the revolving work.

Cover the lathe bed with paper to protect it from small particles of metals

that will be removed during this operation.

3. 4.

Set the rotational speed to the

maximum speed (approximately

1200 RPM, since the polishing is

usually done at high speeds.

Sand papers are available in

different sizes (grits). Use a piece

of 100 to 130 grit abrasive cloth

about 25 mm wide. Fig. 6.68

Fig. 6.68: Abrasive paper

5. Hold the work in the chuck.

Start the machine.

Fig. 6.69: Polishing

6. 7.

Grasp the strip of the abrasive

cloth between your fingers and

held across the work as shown.

Fig. 6.69.

Move the abrasive cloth back and

forth at a steady rate along the

diameter to be polished.



8. 9.

A few drops of machine oil on the

abrasive will improve the finish.

Stop the machine and remove the

piece. Fig. 6.70

Fig. 6.70: Finished part

7. Other Machining Operations

7.1 Boring

Boring is the operation of enlarging an

existing hole with a single point cutting tool

held in a boring bar on the tool post. Fig.

6.71.

Fig. 6.71: Boring Operation

7.2 Parting off

Many parts made on the lathe are

machined out of stock that originally was

cut longer than the finished dimensions.

This allows for center holes drilled in the

ends to be cut off, leaving a finished part.

Parting off is used to cut the workpiece to

the correct final dimensions. Fig. 6.72.

Fig. 6.72: Parting off



7.3 Knurling

Knurling is the process of checking the

surface of a piece of work by rolling

depressions into it. It is an operation of

embossing a pattern on the cylindrical

surface to provide a better grip for the

hand. Fig. 6.73.

Fig. 6.73: Knurling and knurling tool

7.4 Grinding

Grinding can be done in the lathe if the

machine is equipped with an electric

grinding attachment. This permits the

grinding of lathe centers and the

sharpening of cutting tools. Fig. 6.74

Fig. 6.74: Grinding

References

1. Technology of Machine Tools. Seventh Edition, McGraw-Hill

Companies,

2. Machine shop operations and setups, 4th edition, Lascoe nelson

Porter.

3. Machine tool and Manufacturing technology, Steve F. Krar, Mario

Rapisarda, Albert F. Check., Delmar Publishers.

4. en.wikipedia.org/wiki/Machining

http://www.mini-lathe.com



Student’s notes

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Worksheet

1. Calculate the angle ( α to make the taper shown below using the

following dimensions:

D1 = 40 mm

D2 = 20 mm

L = 20 mm

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2. What is the function of the screw thread gauge?

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3. For what purpose do we use the center gauge during the threading

operation?

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4. Mention four uses of threads and give example for each?

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5. Write (T) for true and (F) for false of the following statements:

1. Screw thread is an example of internal thread. ( )

2. In right hand thread the nut is threaded (tightened) in a

clockwise direction. ( )



3. Screw thread gauge is used to set the threading tool in center

with the tool axis at 90° to the centerline of the work ( )

4. The threads in imperial system of measurement are identified

by “The number of threads/inch”. ( )

6. Write the correct terms for the thread shown below:

No. Name

1

2

3

4

5

6

7



7. Match the machining operations from column B with the

suitable drawing in column A?

Write your answer in the box below?

Column A 1 2 3 4 5

Column B

Column A Column B 1)

A) Facing Process

2)

B) Drilling

3)

C) Threading Process

4)

D) Tapering Process

5)

E) Grooving Process



8. Match the lathe operations in column B with the correct tool required for each operation in column A:

Write your answer in the box below?

Column A 1 2 3 4

Column B

Column A Column B

1)

A) Grooving operation

2)

B) Threading operation

3)

C) Drilling operation

4)

D) Turning operation



9. Match the machining operations in column B with their correct definition in column A: Write your answer in the box below?

Column A 1 2 3 4 5

Column B

Column A Column B

1) Make spiral or helical structure on a material.

A) Drilling

2) Make a hole having a specific diameter and depth in a solid material.

B) Threading

3) Increase or decrease the diameter of the workpiece in a uniform rate.

C) Straight turning

4) To move the cutting tool parallel to the longitudinal axis of the workpiece in order to reduce its diameter.

D) Recessing

5) Make a groove having a specific width and depth into the material.

E) Taper turning



10. Match the machining operations in column B with the corresponding picture in column A: Write your answer in the box below?

Column A 1 2 3 4

Column B

Column A Column B

1)

A) Boring

2)

B) Polishing

3)

C) knurling

4) D) Grinding



11. Match the threading terms in column B with their correct definition in column A: Write your answer in the box below?

Column A 1 2 3 4

Column B

Column A Column B

1) The distance from a point on one thread to a corresponding point on the next thread, measured parallel to the axis.

A) Pitch of the thread

2) The largest diameter of an external or internal thread.

B) Minor diameter

3) The diameter of an imaginary cylinder that passes through the thread at a point where the groove and thread widths are equal.

C) Major diameter

4) The smallest diameter of an external or internal thread.

D) Pitch diameter

Date post:	05-Jun-2020
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ATM-412 Machining M6 - Miss Hanna's Classroom...

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