Lathe Machine: Parts, Operations

A lathe machine is a mechanical device in which the workpiece is rotated against a suitable cutting tool for producing cylindrical forms in the metal, wood or any other machinable material.

Figure 1: Lathe machine

Various types of lathe machine tools:

1. Copy Lathe
2. Automatic Lathe
3. Turret lathe machine
4. Engine lathe
5. Bench lathe
6. Chucking lathe
7. Speed lathe
8. Automatic screw machine or a bar machine
9. Numerically controlled lathe

Lathe Machine parts:

Figure 2: Lathe machine parts labeled

Different parts of Lathe:

1. Headstock: Headstock supports the central spindle in the bearings and aligns it correctly. It also houses necessary transmission mechanism for different speeds. It supports the main spindle in the bearings and aligns it properly. It has a mechanism for getting different speeds. Accessories mounted to headstock spindle are 3/4 jaw chuck, lathe center, and lathe dog, collect chuck, face plate, and magnetic chuck.
2. Split nut: When closed around the lead screw, the carriage is driven along by direct drive without using a clutch.
3. Carriage: Carriage moves on the outer ways. Used for mounting and moving most of the cutting tools.
4. Compound rest: Mounted to the cross slide, it pivots around the tool post.
5. Tailstock: Fits on the inner ways of the bed and can slide towards any position the headstock to fit the length of the workpiece. An optional taper turning attachment would be mounted to it.
6. Apron
7. Main Spindle
8. Tool post
9. Cross slide
10. Dead center
11. Hand wheel
12. Bed
13. Led screw
14. Feed rod
15. Clutch
16. Longitudinal & transverse feed control
17. Chip pan
18. Clutch
19. Feed selector

Machining operations that can be performed on a lathe:

machines are highly versatile and capable of some machining processes that produce a wide variety of shapes as the following list indicates:

Figure 3: Various machining operations that can be performed on a lathe

• Turning: [Fig. 3. (a-d)] to produce straight, conical, curved, or grooved workpieces, such as shafts, spindles, and pins.
• Facing: [Fig. 3 (f)] to produce a flat surface at the end of the part and perpendicular to its axis [Fig. 3 (e)], useful for parts that are assembled with other components. Face grooving produces grooves for applications such as O-ring seats.
• Cutting with form tools: [Fig. 3 (g)] to produce various axisymmetric shapes for functional or aesthetic purposes.
• Boring: [Fig. 3 (h)] to enlarge a hole or cylindrical cavity made by a previous process or to produce circular internal grooves.
• Drilling: [Fig. 3 (i)] to produce a hole, which may be followed by boring to improve its dimensional accuracy and surface finish.
• Parting: [Fig. 3 (j)] also called cutting off, to cut a piece from the end of a part, as is done in the production of slugs or blanks for additional processing into discrete products.
• Threading: [Fig. 3 (k)] to produce external or internal threads.
• Knurling: [Fig. 3 (l)] to provide a regularly shaped roughness on cylindrical surfaces, as in making knobs and handles.