LATHE OPERATIONS

1. FACING: It is the operation of finishing the ends of the work to make the piece of required length.
2. Centering : It is the operation of producing conical holes on the ends of work piece.
3. Chamfering : It is done to remove burrs,to protect the end of the work piece from being damaged,to enable nut to pass freely on threaded work piece.
4. Thread cutting :It is the operation of producing helical grooves on a cylindrical or conical surface.
5. Knurling : It is the process of embossing a diamond shaped regular pattern on the surface of a work piece .
6. Grooving : It is the process of reducing the diameter of a work piece over a very narrow surface.

• It is also called Necking.

7. Under-cutting : It is the process of boring a groove or a large hole at a fixed -distance from the end of a hole.

• square nose parting tool is used for this purpose.

8. Parting : It is the operation of cutting a work piece after it has been machined to the desired size and shape.

9.Boring : It is the operation of enlarging and truing a hole previously made by some other process.

10. Reaming : It is the operation of finishing and sizing a hole which has been previously drilled or bored.

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LATHE ACCESSORIES

They are used either for holding & supporting the work or for holding the tool.


1. Centres : Included angle of dead center is usually 60 degrees for general purpose and 75 for heavy work. used to support rotating work.

• Ball center is used to minimize wear &strain , on the work while performing taper turning by set over method.

2. Carriers& catch plate : Used to drive a work piece when it is held between two centers.

• carriers are also known as driving dogs.

3. Chuks : It is work holding device.

1) Four jaw independent chuck: for prismatic jobs,heavy and irregular jobs.

2) Three jaw chuck : used for cylindrical and accurate centering.

3) Combination chuck : Used both as a self centring chuck and as an independent chuck.

4) Magnetic chuck : Used to hold very thin jobs made of magnetic material.

5) Collet chuck : it is used for holding bar stock.

6) Air or hydraulic chuck : used in mass production.

7) Drill chuck : Used to straight shrank drill,reaming etc.

4. FACE PLATE : Used for hold workpieces which cannot be conveniently held between centres or by chucks.

5. Angle plate : They are used in conjunction with a face plate.

6. Mandrel : It is a device for holding and rotating a hollow piece of work that has been previously drilled or bored.

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LATHE COMPONENTS

1. BED : Base of the machine . all parts are located in it.

• guide ways way be flat and inverted v.
• automatic chip disposal is an advantage in inverted v guide ways and ensures accurate alignment.
• made of Grey cast iron alloyed with nickel or chromium.

2. HEAD STOCK : secured permanently on the inner ways at the left hand end of the bed . it provides multiple speeds.

• lathe speeds are arranged in geometric progressions.
• back gear arrangement is used to provide minimum speeds to the spindle.
• spindle of the HEAD stock is made of carbon or nickel-chrome steel.

3. TAIL STOCK : Located on the inner ways at the right hand end of the bed.

• it supports the other end of the work when job is machined between centers.
• it holds the tool for performing operations like drilling,reaming,tapping,counter boringetc

4. CARRIAGE : it supports, move and control the cutting tool,and consists of

• saddle: H shaped casting and carries cross slide & tool post.
• cross slide : it is used to move the tool in a direction perpendicular to the axis of a lathe.
• compound rest : used for obtaining angular cuts & short tapers.
• tool post : located on the top of compound rest to hold the tool.
  

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LATHE MACHINERY

• Lathe is a machine which is used to remove metal from a job to give it the required shape and size.

• it was also called turning machine.

• Lathe is called as a mother of machines as it is suited to a variety of operations like turning,facing,drilling,reaming,tapping,chamfering,knurling etc.

• it is also called turning machine.

• size of Lathe is specified by:

1. Height of the centers measured from the bed.
2. swing diameter over bed.
3. Length between centers.
4. swing diameter over carriage.
5. Maximum bar diameter.
6. Length of bed.
   

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