Study of Lathe

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STUDY OF LATHE

INTRODUCTION

Lathe is the father of all machine tool. It is a basic machine tool probably the most important

one of all, lathe was actually the first machine tool. Lathe is a particular type of machine tool inwhich the work is held and rotated against a suitable cutting tool for the purpose of producing surface of

revolution in any material.

LATHE SPECIFICATIONS:

In order to specify a lathe, a number of parameters could be used on the specific applications.

However, the major elements used for specifications should invariably be based on the

components that would be manufactured in the lathe. The sum of lathe specifications is,

L=Distance between centers.

=Swing diameter over bed.

=Swing diameter over carriage.

=Radius.

=Height of center from bed

DISTANCE BETWEEN CENTERS (L):

This would be specifying the maximum length of the job that can be turned in the lathe.

SWING DIAMETER OVER BED (A):

This specifies the maximum diameter of the job that can be turned in the lathe machine

generally restricted to small length jobs.

SWING DIAMETER OVER CARRIAGE (B):

This specifies the maximum diameter of job that can be turned in the lathe machines with the

job across the cross slide. Other factors should also be specified to fully describe the lathe machine.

1. Horse power of the motor

2. Feed range

3. Accuracy achieved

4. Cutting speed range

5. Screw cutting capacity

6. Spindle nose diameter


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PARTS OF ENGINE LATHE OR CENTER LATHE:

The principal parts of an engine lathe are,

1. Bed,

2. Head stock,

3. Tail stock,4. Carriage,

4.1. Saddle,

4.2. Cross slide,

4.3. Compound rest,

4.4. Tool post,

4.5. Apron.

5. Feed Mechanism,

6. Thread cutting mechanism.

CARRIERS AND CATCH PLATES:

Carriers and catch plates are used to drive a work piece when it is held between two centers.

Carriers or driving dogs are attached to the end of the work piece by a setscrew, and catch plates are

either screwed or bolted to the nose of the headstock spindle.

CHUCK:

A chuck is one of the most important devices for holding and rotating a piece of work in a

lathe. Work piece of short length, and large diameter or irregular shapes, which cannot be

conveniently mounted between centers, are held quickly and rigidly in a chuck.

TYPES OF CHUCKS:

1. Four jaw independent chuck

2. Three jaw universal chuck

3. Air or hydraulic operated chuck

4. Magnetic chuck

5. Collet chuck

6. Combination chuck

7. Drill chuck


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GANG MANDREL:

This has a fixed collar at one end and a movable collar at the threaded end, which may be

adjusted, to this position by a nut. The mandrel is used to hole a set of hollow work piece between

two collars by tightening the nut.

EXPANSION MANDREL:There are different types of expansion mandrels. The mandrel consists of tapered pin, which

is driven into a sleeve that is parallel outside and tapered inside the sleeve has three longitudinal

slots, two of which are cut nearly through, and the third splits it completely.

RESTS:

A rest is a mechanical device which supports a long slender work piece, which is turned

between centers or by a clutch, at some intermediate point to prevent bending of the work piece due

to its own weight and vibrations set up due to the cutting force that acts on it.

STEADY REST:

A steady rest shown in Fig consists of a cast iron base, which may be made to slide on the

loath bed ways and clamped at any desired position where a support is necessary.

Study of Lathe

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