lathe parts and lathe types

1. THE LATHE

2. INTRODUCTION
• Lathe is one of the oldest important machine tools in the metal working
industry. A lathe operates on the principle of a rotating work piece and a
fixed cutting tool.
• A rope wound round the work with its own end attached to a flexible
branch of tree and other end being pulled by man caused job to rotate
intermittently. With its further development a strip of wood called “lath”
was used to support the rope and that is how the machine came to be
known as “lathe”.
• The cutting tool is feed into the work piece, which rotates about its own
axis, causing the work piece to be formed to the desired shape.
• Lathe machine is also known as “the mother/father of the entire tool
family.

3. HISTORY
• The Lathe Machine is one of the oldest and most important machine
tools. As early as 1569, wood lathes were in use in France. The lathe
machine was adapted to metal cutting in England during the Industrial
Revolution.
• Lathe machine also called “Engine Lathe” because the first type of
lathe was driven by a steam engine.

4. INVENTOR OF CENTRE LATHE
• Henry Maudsley was born on an isolated farm
near Gigghleswick in North Yorkshire and
educated at University Collage London. He was
an outstandingly brilliant medical student,
collecting ten Gold Medals and graduating with
an M.D. degree in 1857.
• Source :- Internet

5. Fig:- Lathe Machine

6. FUNCTION OF THE LATHE
The main function of a lathe is to remove metal from a piece of work to
give it the required shape and size.
Operation Motion of Job Motion of Cutting Tool
Turning Rotary Forward translation
Boring Forward translation Rotation
Drilling Fixed Rotation as well as translator feed
Planing Translatory Intermittent translation
Milling Translatory Rotation
Table 1 :- Nature of Relative Motion For Various Cutting Operations

7. • Source :- Internet
LATHE PARTS
Fig:- Lathe Parts

8. Block Diagram of Lathe
Fig:- Block Diagram of Lathe
• Source :- Internet

9. TYPES OF LATHE
Lathes of various designs and constructions have been developed to suit the various
conditions of metal Machining. But all of them employ the same fundamental principle
of operation and perform the same function.
The types generally used are:
• The Speed Lathe
• The Engine Lathe or Centre Lathe
• The Bench Lathe
• The Capstan and Turret Lathe
• Special Purpose Lathe
• Automatic Lathe

10. This term ‘Engine’ is associated with the lathe owing to the fact that early lathes
were driven by steam engine. It is also called center lathe. The most common
form of lathe, motor driven and comes in large variety of sizes and shapes.
ENGINE LATHE
Fig:- Engine Lathe
• Source :- Internet

11. BENCH LATHE
This is a small lathe usually mounted on a bench. It has practically all the parts of an
engine lathe or speed lathe And it performs almost all the operations, its only difference
being in the size. This is used for small and precision Work.
Fig:- Bench Lathe

12. A lathe in which the work piece is automatically fed and removed without use of
an operator. It requires very less attention after the setup has been made and the
machine loaded.
AUTOMATIC LATHE
Fig:- Automatic Lathe
• Source :- Internet

13. Distance Between Centres
(Radius)
One Half of Swing
LATHE SIZE AND CAPACITY
Fig:- Lathe Size
The capacity of a lathe is expressed in two dimensions. The maximum part diameter or swing,
and the maximum part Length or distance between centres.

14. • This is heavy rugged casting made to support the working parts of lathe and also guide and
align major parts of lathe.
• Made to support working parts of lathe.
• On top section are machined ways.
• Guide and align major parts of lathe.
 Bed is the base of lathe.
 Bed is made of cast iron .
 The top of Bed has two guide ways to provide support to the sliding surfaces for the
carriage & tail stock.
LATHE BED
Fig:- Lathe Bed

15.  Head stock is permanently fastened to the left end of
the lathe bed
FUNCTION OF HEAD STOCK:
 To support the spindle
 To house the main drive
 SPINDLE: Spindle is the hallow rotating shaft used
for holding the work piece
HEAD STOCK
Fig:- Head Stock

16. • Contains number of different-size gears
• Provides feed rod and lead-screw with various speeds for turning and thread-cutting
operations
QUICK CHANGE GEAR BOX
Table:- Standard Thread Cutting Gear Values
Fig:- Gear Arrangement

17.  Carriage is located in b/w head stock &
tail stock of the lathe bed
 The carriage travels along the machine’s
bed ways, parallel to the It slides along
the guide way on the lathe bed.
FUNCTION OF CARRIAGE:
 To hold the cutting tool & give
longitudinal or cross feed to the cutting
tool.
CARRIAGE
Fig:- Lathe Carriage

18. 1. Saddle: It is a part of the carriage which slides along the guide
ways of lathe bed
2. Apron: It is the mechanism of carriage used for manual &
mechanized movements of the carriage along longitudinal axis
of the lathe
3. Cross- Slide: It is part of carriage which is mounted on saddle.
It gives cross feed to the cutting tool
4. Compound Rest: Mounted on top of cross-slide. Can be
swiveled to any angle in horizontal plane to facilitate taper
turning
5. Tool Post: Mounted on compound rest. It’s function is to hold
the cutting tool
Parts of Carriage

19. TAPER TURNING BY SWIVELLING THE COMPOUND REST
This method employs the principle of turning taper by rotating the work
piece on the lathe axis and feeding the tool at an angle to the axis of rotation
of the work piece. The tool mounted on the compound rest is attached to a
circular base, graduated in degree, which may be swivelled and clamped at
any desired angle.
Taper angle(α) calculated by
Where; D= largest diameter. d= Smallest diameter
l= length of the tapered portion.
Fig:- Swivelling The Compound Rest
Arrangement.
tanα=
𝐷−𝑑
2𝑙

20. • Located at the top of the compound rest.
• Hold the tool.
• Tool holders are made of different designs according to the shape and
purpose of the cutting tool.
TOOL POST
Fig:- Different Types of Tool Post

21.  Tail stock is located at the right of the lathe
bed.
 It can be moved along the guide way on the
lathe bed & can be clamped at any position
on the lathe bed.
FUNCTION OF TAIL STOCK:
 To hold the tool’s like drill, reamer, or tap
for cutting operations such as drilling
reaming tapping
 It hold’s dead center which can support the
long work pieces during the machining
operation.
TAIL STOCK
Fig:- Tail Stock

22. • Work to be turned between centers must have center hole
drilled in each end
 Provides bearing surface
• Support during cutting
• Care to adjust and lubricate occasionally
LATHE CENTERS
Fig:- Lathe Centres

23. • Used extensively for holding work for machining operations
 Work large or unusual shape
• Most commonly used lathe chucks
 Three-jaw universal
 Four-jaw independent
 Collet chuck
 Magnetic Chuck
CHUKS

24. Three jaw
Chuck
• For holding cylindrical
stock centered.
• For facing/center drilling
etc.
Four jaw
Chuck
This is independent chuck
generally has four jaws , which
are adjusted individually on the
chuck face by means of adjusting
screws.
Fig:- Chucks
• Source :- Internet

25. Collet chuck is used to
hold small work pieces.Collet Chuck
Magnetic
Chuck
Thin jobs can be held by
means of magnetic chucks.
Fig:- Chucks
• Source :- Internet

26. Steady Rest
Steady rest is made of cast iron. It may be made to slide on the lathe Bed ways and clamped
at any desired position where the workpiece needs support. It has three jaws. These jaws can
be adjusted according to the diameter of the work. Machining is done upon the distance
starting from the headstock to the point of support of the rest. One or more steady rests may
be used to support
Work
Hinge
Jaw
Fig:- Steady Rest

27. Follower Rest
It consists of a ‘C’ like casting having two adjustable jaws to support the workpiece. The
rest is bolted to the back end of the carriage. During machining, it supports the work and
moves with the carriage. So, it follows the tool to give continuous support to the work to
be able to machine along the entire length of the work. In order to reduce friction between
the work and the jaws, proper lubricant should be used.
Jaw
Carriage
Work
Fig:- Follower Rest