Types of lathe

TYPES OF LATHE

To suit for different machining conditions, the various types of lathes have been developed. Lathes are classified in many ways with respect to size, design, method of drive and purposes. The different types of lathes are as follows.

1. Speed Lathe

(a) Wood working lathe

(b) Metal spinning lathe

(c) Metal turning lathe

(d) Polishing lathe.

2. Engine lathe

(a) Step cone pulley drive lathe

(b) Geared lathe

(c) Variable speed lathe.

3. Bench lathe

4. Tool room lathe

5. Semiautomatic lathe

(a) Capstan lathe

(b) Turret lathe

6. Automatic lathe

7. Special purpose lathe

(a) Crankshaft lathe

(b) Wheel lathe

(c) Duplicating lathe

8. Copying lathe.

1. Speed Lathe

The speed lathe is the simplest of all lathes. It consists of headstock, bed, tailstock and adjustable slide. There is no lead screw, feed box and apron mechanism. The tool is only fed by hand. Usually, this lathe is driven by a variable speed motor fitted in the headstock. The spindle is driven by a high-speed motor through belts and step cone pulley. The work is held between centres and rotated at high speed (1200 to 3600rpm). The tool is supported on the tool post and fed by hand. It is mainly used for wood turning, spinning and polishing works.

2. Engine Lathe or Centre Lathe

Engine lathe is more important and widely used. In earlier days, it was driven by a steam engine and hence, it was called engine lathe. It has the various parts such as headstock, tailstock, carriage and bed. Automatic feed is also available. It differs from the speed lathe. It is provided with additional features for controlling the spindle speed and the feed of cutting tool, feed rod, lead screw and change gears are provided. The tool may be fed transversely or longitudinally. The tool is fed manually or automatically to remove the metal. Engine lathes are usually driven by a constant speed motor mounted on a lathe. It is used for medium and large type of work. It is used for many operations such as turning, taper turning, threading, drilling, knurling, reaming and forming.

3. Bench Lathe

It is a small lathe which can be mounted on a workbench. It has all parts similar to a centre lathe which is used for many works. The only difference is smali in size and mountings. It is used for machining small parts cheaply and accurately at the rapid rate.

4. Tool Room Lathe

A tool room lathe consists of all necessary attachments required for accurate and precision machining. It has more range of speed and feed. It is equipped with a central steady rest, quick change gear mechanism, taper turning attachment, lead screw, feed rod, accurate collet chuck, thread cutting attachment, pump for coolant, micrometer stop, follower and centre rests etc. This lathe is too costly due to its high accuracy and precision attachments.

5. Semiautomatic Lathe

As the name implies, some operations are manually done and some operations by automatic means. Capstan and turret lathes are of this type. These lathes are heavy lathes used for mass production. The headstock is heavier than the centre lathe and it has wide range of speed and feed. In some lathes, there is no tailstock. In those cases, the tailstock is replaced by a turret head. The number of tools may be fitted to the turret head. They are fed into the work in a proper sequence. There are two tool posts, a front tool post and rear tool post. The front tool post carries four tools. The rear tool post carries a parting tool. Many operations can simultaneously be done by the front tool post, rear tool post and turret. Hence, the production time is minimized. The accuracy will be more. These lathes are used in mass production. They are used to produce identical parts.

6. Automatic Lathe

In this lathe, all operations and job handling movements are automatically done. It is a high-speed heavy duty lathe which is used for mass production. The loading and unloading of works are automatically done in this type of lathe. There is a camshaft for carrying a number of cams. The cams will do the speed changing, feed changing and tool changing. After the initial setting of tools, it will automatically do all operations till the job is parted off. After completing one cycle, the machine will repeat the same operation and bence, it only will produce identical parts. But, the machining time is very less. One operator can handle many lathes at a time.

7. Special Purpose Lathes

These lathes are specially designed for carrying out specific operations. These lathes are used to do various operations that cannot be done on ordinary lathes. The headstock, tailstock and carriage of these lathes are made according to the requirements of special operations to be performed. For example, a shell lathe is used for turning shells only. A wheel lathe is efficiently used for making locomotive wheels. A crankshaft lathe can only be used for turning crankshafts.

8. Copying Lathe

The tool of this lathe follows a template or master through a stylus or tracer. The tracer is connected to the cutting tool through hydraulic devices. According to the tracer movement, the tool moves to machine the job.