Unit 2

2 Marks

1.what is swing diameter?

The largest diameter of work that will revolve without touching the bed and is twice the height of the center measured from the bed of the lathe.2.write the specification of a typical lathe.

1.length of bed.

2.maximum distance between dead and live centres.

3.type of bed i.e.straight,semi gap or gap type.

4.the height of centre from the bed.

5.swing over the bed.

6.swing over the cross slide.

7.width of the bed

8.spindle bore

9.spindle speed.

10.H.P. of main motor and rpm.

11.number of spindle speeds

12.spindle nose diameter

13.feeds

14.floor space required

3.what are the various operations can be performed on a lathe.

1.turning

2.facing

3.forming

4.knurling

5.chamfering

6. thread cutting

7.drilling

8.boring

9.recessing

10.tapping

11.grooving etc

4.what provisions are made to accomadate other parts of a lathe on the bed?

Guide ways

5.what are types of headstocks?

1.back geared 2.all geared type6. what is the difference between live center and dead center?

1.live center drives rotates along the work pieces

2.dead center just support the other end of the work pieces

7. write down the names of four lathe accesories?

lathe centers,catch plates,carriers,chucks,mandrels and rests.

8.what is compound rest?

member or part which is mpunted on the top of the cross slide having a base graduated in degrees.

9.what are the four types tool post?

single screw tool post,open side tool post,four bolt tool post,four way tool post

10.How the cutting tool is fixed on the single screw tool post and how can you tool height ?

A single screw tool is used to hold omly single tool which are clamprd by clamping screw.

the tools height can be vary by adjusting a rocker placed on the tool post

11.why it is essential that cuuting point of the tool should be level with its spindle center while maching taper on a work piece ?

It is done to avoid eccentric taper

12.what is an apron ?

apron is intergral part of several gears ,levers and clutches which are mounted with saddle for moving the carriage along with lead screw while thread cutting

13.what is semi automatic lathe?

the lathe in which all the machining operation are performed operation are performed automatically but loading and unloading of work piece ,coolant on or off are performed manually

14.define feed ?

feed is defined as the movement of the tool relative to the work and work piece by form tool

15 state the various feed mechanism used for obtaining automatic feed?

1.tumbler gear mechanism.

2.quick change gear box.

3.tumbler gear -quickchange gear box.

4.apron mechanism.

16 What are the advantages of using collect chuck?

Job setting will be easy and quicker.

Heavy cut can be done

17 Define steady and follower rest?

Steady rest:

It is fixed on the bed ways of the lathe by clamping the bolts.

Follower rest:

It is mounted on the saddle and moves together with the tool.

18 What is the purpose of mandrel and what are its types?

Mandrel are used for holding hollow work piece.

Types:

Plain mandrel

Gang mandrel.

Cone mandrel

Collar mandrel

Special mandrel

Step mandrel

Expansion mandrel

19 What is the application of air operated chuck?

Heavy work piece are mounted with the help of air operated chuck because they will require more power to hold the workpiece.

20 Why were the power chuck developed?

Power chuck are primarily developed for the application of work holding device for automatic machines , numerical control and CNC machines.

21 What is reaming and boring operation?

Reaming:

It is the operation of finishing and sizing of already drilled hole.Boring:

It is the process of enlarging a already drilled hole.

22 What is drilling operation?

Drilling is the operation of producing cylindrical hole in a workpiece.

23 What is eccentric?

The axis of one cylinder is offset with the axis of the other cylinder.

24 Write down the formula for calculating tail stock set over distance.

Set over, S = D-d/2l * L= L tan

D- Bigger Diameter

d- Smaller diameter

l- Length of the workpiece

25 Define the term conicity.

The ratio of the difference in the diameters of the taper in the length,

K=D-d/l

D- Bigger Diameter

d- Smaller diameter

l- Length of the workpiece

26 Define tapper.

Tapper is defines as a uniform change in the diameter of workpiece measured along its length.

27 What is meant by tapping?

The tapping is the operation of forming internal thread of small diameter by using a multi point tool.

28 What is milling operation?

The operation of removing metals by using rotating having multiple cutting edge.29 What is thread cutting operation?

It is the operation of producing continuous helical grooves on a cylindrical workpiece.30 Write down the formula for calculating taper turning angle by compound rest method.

tan = D-d/2l

D- Bigger Diameter

d- Smaller diameter

l- Length of the workpiece

31 Name any 4 tool holding devices.

Multiple cutter holder

Offset cutter holder

Sliding cutter holder

Knee tool holder

32 . State any two specifications of capstan and turret lathe.

Number of spindle speeds

Number of feeds for the turret or the saddle.

33 What type of mechanism is used for indexing the turret head for the next operation?

Geneva or indexing mechanism.

34. What are the various types of cross slides?

Reach over type

Side hung type.

35. What are the components that can be turned on a copying lathe?

Cam shaft

Crank shaft

Journal bearings36. What are different drives used in copying lathes?

Mechanical drive

Air drive

Hydraulic drive

37. What are the advantages of automatic lathes?

Mass production of identical parts.

High accuracy is maintained

Time of production is minimized.

Bar stock is fed automatically

38. Define automatic machine.

Automatic machine are simply automats are machine tools in which all the operations required to finish off the work piece are done automatically without the attention of the operator.

39. State the advantages of swiss type screw cutting machine.

It has five tool slides.

Wide range of speed.

Rigid construction

Micrometer tool setting.

Numerous working station

40. What are the four major parts of swiss type automatic lathes?

The sliding head stock through which the bar stock is passed and gripped by a carbide lined guide bush.

The cam shaft controlling the bar stock and the cutting tool movements.

The tool brackets supporting five tool slides and the bush for stock.

Auxillary attachments for performing various operations such as knurling,drilling,taper,etc.,

41. Compare the parallel action and progressive action multispindle automatic lathes.

S.NOPARALLEL ACTION MACHINEPROGRESSIVE ACTION MACHINE

1.

2.

3.

4.Same operation is done on all jobs in all the spindles

In one cycle, the number of components produced simultaneously is equal to the number of the spindles

Rate of production is high.

If anything goes wrong in one station the production in that particular station only affectedDifferent operations are done on the jobs at each station one after the another

It is not so. The number of components produced in one cycle is not equal to the number of spindles

Rate of production is moderate.

If anything goes wrong in one station the production is completely affected in all the stations.