Lathe Machine Components and Their Functions

A lathe is a machine tool used to remove unwanted material from the work piece. This machine is the most versatile machine and is widely used all over the world, so it is dubbed the “mother of all machines”.

In this article, we will explain some of the parts of a lathe machine and their functions.

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Lathe Machine Components

1. Bed

The bed is a solid base that connects the headstock, and allows the carriage carrier and tailstock to be moved parallel to the shaft axis.

Generally, on the bed there are ways in the form of hardened and grounded parts and hold the carriage and tailstock in a predetermined path. There are three types of beds that are commonly used, including inverted “V” beds, flat beds, and combinations of flat beds and “V” beds.

2. Headstock

The headstock is the part of the bed that is located at the far left. The headstock serves to transmit power to various parts of the lathe.

On the headstock, there is a main spindle, a speed change mechanism, and a gear change mechanism.

In general, the headstock must be made as strong as possible to prevent cutting forces from distorting the built housing, where it causes harmonic vibrations that will transfer to the work piece and will reduce the quality of the finished work piece.

3. Chuck

A chuck is a part used to hold work pieces together, especially those that are short in length and large in diameter, or are irregular in shape and cannot fit easily between centers. This part can be attached to the lathe by screwing on the spindle nose.

There are 4 types of chucks, namely:

  • Independent or four jaw chuck

These chucks are used for holding irregularly shaped objects, casting rough squares, or octagonal shapes in a job, where the hole must be positioned in the center.

This chuck consists of four jaws, as the name implies, and each jaw is moved independently and adjusted with a lock to hold the job.

  • Universal or three jaw chuck

These chucks are used to hold round, hexagonal rods, or other symmetrical objects. This chuck consists of three jaws that move simultaneously by turning the key and the work piece automatically stays in the center of the chuck opening.

  • Collector chuck

This chuck is used to hold small bars (below 63 mm). These chucks are widely used in places where work is required such as in capstan lathes or automatic lathes.

  • Magnetic chuck

Is a type of chuck that is commonly found on modern lathes. These chucks can be either permanent magnet or electrically operated.

4. Tailstock

The tailstock is a drill and center mount located opposite the headstock. On the tailstock there is a spindle, which moves longitudinally, but does not rotate.

The spindle is generally pointed and serves to hold drill bits, centers, and other tools. The tailstock is generally placed along the bed and clamped in a position determined by the work piece.

5. Carrier

The carrier is the component located between the headstock and tailstock. Carriers function to support, guide, and feed tools to work during operations.

6. Saddle

The saddle is an H-shaped casting mounted on the top of the ways of the lathe. The saddle serves to support cross-slides, compound rests, and tool posts.

7. Cross Slide

Cross slides are generally equipped with the tail of the female peg on one side and mounted on the saddle with the male peg.

The top surface of the cross slide is generally equipped with a T slot to allow for rear tool post or cooler mounting.

The conveyer basically provides the cross motion which is mounted or occurs automatically on the cutting tool.

8. Compound Rest

The compound rest is at the top of the cross slide. This section supports the tool post and cutting tool in various positions. Compound rests are generally required to change angles and drill short tapers and shapes in the shaping tool.

9. Tool Post

Tool post is generally mounted on a compound rest. This section is used to hold various cutting tool holders.

The holder rests on a wedge formed at the bottom to fit a concave ring (segmental type), which allows the cutting tip height to be adjusted by tilting the tool.

This section is generally installed at the top of the slide. This section moves due to the movement of the saddle, cross slide, and top slide. There are three types of post tools that are commonly used, including:

  • Tool post ring and rocker, this type generally consists of a circular tool post with a slot to accommodate the tool or tool holder
  • Quick change post tool
  • Square head post tool

10. Apron

The apron is generally tied to the saddle and hung in front of the bed. Aprons generally consist of gears and couplings to transmit movement from the feed stick to the carrier, and a split nut which is connected to the lead screw during thread cutting.

There are two types of aprons that are commonly used:

  • Mechanism of Incorporating drop worm
  • Friction or dog clutches.