1. Facing : The lathe operation of finishing the ends of the work, to make the end flat and smooth and to make the piece of the required length, is called facing.
2. Straight (ar Cylinderical) Turning:
The lathe operation of producing perfectly cylinderical external surface of the work, is known as cylinderical or straight turning. It may also be simply known as turning.
3. Shoulder Turning: The lathe operation of finishing the sides or shoulders of a stepped work, is known as shoulder turning.
4. Taper Turning: The lathe operation of finishing or producing an external conical surface on a work is known as taper turning.
5. Chamfering: The lathe operation of bevelling, the extenal edge of the work-piece with the help of a chamfering tool is known as chamfering. Chamfer provided on the edge of a work piece helps to avoid injury to the hand while handling it and also facilitates easy assembly of wo mating parts. Chamfering is an esential operation after thread cutting so that the nut may pass freely on the threaded work-piece.
6. Forming: The lathe operation of turning a convex, concave or any irregular shape is known as form-turning or forming.
Forming may be accomplished by the following methods:
(i) Using a form tool.
(ii) Using simultaneous cross and longitudinal feed of the tool.
(iii) Tracing or copying a template.
7. Grooving: The lathe operation of reducing the diameter of a work-piece over a very narrow surface is known aş grooving. The tool of appropriate shape should be fed into the revoluing work upto desired depth at right angles to the centre line of the work-piece.
8. Parting-off: The lathe operation of cuting a work-piece from a long bar after it has been machined to the desired size and shape, is known as parting-off. The tool should be fed into the revolving work at right angles to the cemtre line of the work-piece.
9. Knurling: The lathe operation of checking the surface of work piece of rolling depression into the surface, is known as knurling.
10. Spinning: The lathe operation of forming a thin sheet of metal by revolving the workpiece at high speed and pressing it with a spinning tool against a "former" attached to the headstock spindle, is known as spinning. This operation may be carried out in an ordinary centre lathe or a specially designed lathe known" as spinning lathe.
11. Filling : The operation of finishing an external surface generally with the help of a flat single cut file, is known as filling a lathe work.
12.Polishing: The lathe operation of improving surface quality of a revolving work piece against successively finer graded of emery cloth is known as polishing in a lathe.
13. External Thread Cutting: The lathe operation of cutting a helical groove on an external cylinderical or conical surface by feeding the tool longitudinally to the revolving work, is known as external thread cutting. The work is held between centres or in a chuck. The longitudinal field is equal to the pitch of the thread to be cut and is imparted in calculated amounts to the tool from the main spindle via change gears (or feed box), leadscrew and saddle. This operation is one of the most important operations performed in a lathe.
14. Eccentric Turning: The operation of tuming a cylinderical surface of a workpiece with its axis parallel to, but not coincident with the normal axis of the workpiece, is known as eccentrie turning.
15. Drilling: The opcration of producing a hole or enlarging an already existing cylinderical hole with the help of a drilling tool (or-drill), is knownas drilling.
16. Boring: The operation of enlarging an already existing cylinderical hole with the help of a boring tool is known as boring.
17. Counterboring: The operation of enlarging a small end portion with a boring tool of an already existing hole in a workpiece, is known as counterboring.
18. Taper Boring: The operation of producing a taper hole from an already existing or drilled hole, with the help of a boring tool, is knòwn as taper boring.
19. Reaming: The operation of further finishing and sizing an already drilled or bored hole with a reaming tool (called reamer), is known as reaming,
20. Internal Threading : The lathe operation ofcutting a helical groove on an intermal cylinderical surface (a drilled or bored hole) by feeding the tool longitudinally to the revolving work, is known as internal threading.
21.Under Cutting: The operation of enlarging the diameter of a small surface within the length of a drilled or bored hole is known as under cuttng,
22. Spring Winding : The operation of making a coiled spring from a spring wire in a lathe machine is generally knownas spring winding.
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