Lathe: Specification of a Lathe, Classification of a Lathe, Speed Lathe, Engine Lathe or Centre Lathe, Turret Lathe, Capstan Lathe, Tool room Lathe, Bench Lathe, Gap bed Lathe, Hollow Spindle Lathe, Vertical turret Lathes, Automatic Lathes, Special purpose Lathes

What is Lathe ?

Lathe removes undesired material from a rotating work piece in the form of chips with the help of a tool which in traversed a cross the work and can be fed deep in work. 

The tool material should be harder than the work piece. The work piece in held securely and rigidly on the machine. 

The cutting tool is rigidly held and supported in a tool post and is fed against the revolving work while the work revolves about its own axis the tool is made to move either parallel to it or at an inclination with their axis to cut the desired material. It produces cylindrical surface if it is fed at an inclination.

Specification of a Lathe

Specification of a Lathe: 

A lathe is generally designed by

a) Swing i.e. the largest work diameter that can be swing over the lathe bed.

b) Distance between head stock centers.

Classification of a Lathe: 

According to size, design, method of drive, arrangement of gears, different precision classes and purpose.

i) Speed Lathe: 

It is so named because of the very high speed of head stock spindle. It is a simplest form of lathe and consists a simple head stock, a tail stock and tool post. It has no gear box, lead screw and carriage. Tools are hand operated. Cone-pulley is the only source provided for the speed variation of the spindle. Mainly used for wood turnig, metal spinning and polishing operations.

ii) Engine Lathe or Centre Lathe: 

It is most widely used one. Its name is derived from the fact that early machine tools were driven by a separate engine or from a central engine with over head belts and shafts. The stepped cone- pulley or geared head are often used for varying the speed of lathe spindle. A tail stock is provided to facilitate holding the work between the centers and permit the use of tools like drills and taps etc. The cutting tools are controlled either by hand or by power and can be fed both in cross and longitudinal directions with ref to lathe axis with the help of a carriage feed rod and lead screw. A wide range of attachments can be fitted on it to increase its utility. These are available in sizes to handle up to 1 m dia jobs and 1 to 4 m long.

iii) Turret Lathe: 

It is a production machine used to perform a large number of operations simultaneously. Several tools are set on a revolving turret to facilitate doing large number of operations on a job in minimum time. An index able square tool post is provided on the cross slide for mounting the turning and parting off tools.

The turret usually accommodates six tools for different operations like drilling counter sinking, reaming, tapping etc, which can be successively brought in to working positions by indexing the turret. Some special tool holders to perform simultaneous multi tool operations are also available. They are widely used be repetitive batch production.

iv) Capstan Lathe: 

It is similar to turret lathe and incorporate capstan slide which moves on an auxiliary slide and can be clamped in any position. It is best suited for fast production of small parts because of its light weight and short stroke of capstan slide.

v) Tool room Lathe: 

It is the modern engine lathe which is equipped with all necessary accessories for accurate tool room work. It is a geared head driven machine with considerable range in spindle speeds and feeds. It is suited for production of small tools, dies, gauges etc.

vi) Bench Lathe: 

It is a small lathe which can be mounted on the work bench for doing small precision and light jobs.

vii) Gap bed Lathe: 

In these lathes, a gap is provided on the bed near the head stock with a view to handle jobs having flanges or some other producing parts. Very often q removable portion is provided in the bed so that when not required, it can be inserted.

viii) Hollow Spindle Lathe: 

These lathes are provided with spindles having large through bores in order to facilitate turning the ends of long tubular work pieces. The long jobs are supported on a steady or some other out board support.

ix) Vertical turret Lathes: 

These have vertical orientation and are use for turning large components which can be conveniently mounted on the machine table. The turret head moves in two axes to enable turning, boring and facing.

x) Automatic Lathes: 

They are designed for all working and job handling movements of the complete manufacturing a job are done automatically. Operator participation is not required during the operation. In semi-automatic lathes, mounting and removal of work is done by the operator and all other operations are performed by the machine automatically.

xi) Special purpose Lathes: 

These are desired to suit a definite class of work and to perform a specific operation only. They prove to be more efficient and effective as compared to the common engine lathe.

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