The document describes the lathe, which is a versatile machine tool used to shape materials by rotating the workpiece against various cutting tools. It discusses the main components of a lathe like the bed, headstock, tailstock, carriage, and feed mechanism. It also explains common operations performed on a lathe like turning, drilling, boring, knurling, and tapering.

1. A “lathe” is one the earliest and
most versatile machine tool used in
any workshop. Hence it is also
called as the father of all the
machine tools.

2.  The Lathe has become a general purpose
machine tool which is widely used in the
production works.
 The job to be machine the tool is held and
rotated in a lathe chuck and the cutting tool
is moved relative to the job. Since the
cutting tool material is harder than the work
piece, the metal relatively is moved from the
job. If the tool moves parallel to the axis of
rotation of the work piece, cylindrical
surface is produced, if it moves
perpendicular to the axis, it produces a flat
surface.

3.  The various operations performed on lathe
are facing, turning, taper turning, threading,
knurling, drilling, boring, reaming,
chamfering, etc.

4.  The most common type of lathe is center
lathe. It is named so because a work is held
between two centers i.e. the head stock(live
center) and the tail stock(dead center).
The principle parts of a lathe are
 Bed
 Head stock
 Tail stock
 Carriage
 Feed mechanism

6.  It is the base or foundation of the lathe. It is
very heavy, rugged and single piece casting made
of grey CI or Nickel alloy CI to support the entire
parts of the lathe.
 It carries a headstock on its left and tailstock on
its right end. Carriage is mounted on middle of
the bed.
 Bed is carefully machined and scraped because
lathe accuracy is purely depends upon the
accuracy of the bed.
 The guide ways may be flat or V shaped and
machined with high precision to ensure accurate
alignments of various parts fitted on the bed.
The guide ways also serve as rails to carriage
with tool post and tail stock in line with spindle.

7.  The head stock id permanently mounted at the
left end of the bed.
 The head stock receives the drive from an
electric motor and it makes use of cone pulleys
and gears for getting various spindle speed for
rotating the work piece at various levels.
 The head stock contains work holding devices
like chucks, face plates and dog plates to hold
and drive the work piece.
 All the lathes receive their power with the Help
of the head stock.
There are two types of head stock available to
transmit the motion to the job.
 Step cone pulleys driven (Belt driven) head stock
and
 Gear driven head stock.

8.  It is located at the right hand end of the bed
and can be clamped at any position by using
lock lever.
 It mounts the dead center and can be moved
along with the lathe bed for accommodating
work pieces.
 The tail stock hand wheel is used to move
the tail stock in or out of the tail stock
casting and a spindle lock handle is also used
to lock the spindle at any position.
 It is also used to hold drill, reamer or tap for
drilling, reaming or tapping operation.

9.  This is a device used for mounting and
moving the cutting tool between the head
stock and the tail stock it has the following
parts
 Saddle: The base of the carriage is the
saddle. It is a “H” shaped component and
slides along the guide ways of the lathe bed.
 Cross-slide: It is mounted in the saddle and
moved by the means of the feed screw that
is controlled by a small hand wheel. It also
provides the cross movement i.e., towards or
away from the operator to the cutting tool.
It supports the compound rest and tool post.

10.  The compound rest:
 It is mounted on the top of the cross slide and used to
support the cutting tool.
 It permits both parallel and angular movements to the
cutting tool
 This angular movement is used for angular cuts and tapper
cutting.
 Tool post:
 The tool post is mounted on the compound rest and slides
in a T-slot.
 It clamps the cutting tool and tools holder in a desired
position to provide convenient working conditions.
 Apron:
 It is attached to the front of the carriage.
 It contains gears, clutches and levers for operating the
carriage by hand and power feeds.
 The apron hand wheel can be turned by hands to move the
carriage along the bed of the lathe.
 The automatic feed lever is also used to engage power
feeds to the carriage ad cross-slide

11.  The movement of the tool relative to the
work is called as feed.
 The power is transmitted to the apron
through feed mechanism by rotating the feed
rod through the gearing and clutch
arrangements in the apron.
 For thread cutting operations, the drive is
given by a lead screw by a direct connection
between the apron and lead screw by means
of a split nut.

12.  Facing
Facing is the operation of making the ends of a
work piece flat. The work piece is held in
chuck. The tool is set exactly to the center
point of the work piece and slightly inclined
to the work piece. The work piece is rotated
and tool is fed perpendicular to the axis of
rotation of work piece.

13.  Turning:
Turning is the operation of reducing the
diameter of cylindrical work piece to the
required dimensions. The work piece is held
in the chuck. The work piece is rotated and
tool is fed parallel to the axis of rotation.
 Plain turning is the uniform reduction in the diameter of the work piece
throughout its turned length.
 Work piece may have two or more diameter to be turned or it can involve
steps of different diameters. Turning of such steps is called as step
turning.

14. Drilling:
 Drilling is the operation of producing a
cylindrical hole in the work piece. Here the
work piece is revolved in the chuck and the
drill is fed from the tail stock.

15.  Boring:
 It is the operation of enlarging a hole which
is already made by drilling. Work piece is
clamped in the chuck and rotated. The tool
is fitted in the tool post and is fed
longitudinally in to the work piece. The
depth of cut is given through cross slide.

16.  Knurling:
 Knurling is the process of embossing a diamond shaped
pattern on the surface of a work piece. This is done to
provide gripping surface in the work piece. This operation
is performed by a special knurling tool which consists of
hardened rollers with teeth cut on their surface. The tool
is held on the tool post and rollers are pressed against the
revolving work piece to produce diamond shape in the
surface of the work piece.

17.  Taper turning:
 Taper turning is the operation to produce a
conical surface by gradual reduction in
diameter from a cylindrical work piece. A
tapered job is obtained by feeding the tool
at a required angle to the axis of rotation of
the work piece.