Lathe and Drilling Machines

Lathe and drilling machines
Manufacturing process
• It is a process which involves the conversion

of raw materials into desired product.
Methods involved
• Material removal
• Assembly or joining process
• Finishing process
Material removal operation
• It involves removal of extra material from the
given material to obtain required dimension of
product.
• Material removal can be in small scale or large
scale
small scale – fitting, craftwork etc
large scale – industrial products.
Tool
• A tool is a device use to carry out various
manufacturing operation.
– Hand tools.
– Machine tools
Hand tools
• Tools which are used manually by human
effort.
– Files
– Hacksaw
– Hammer
– Chisels etc
Machine tools
• Defined as power driven machine which
accomplishes the cutting operation or
machining operations.
• Machine tools includes lathe, milling ,
drilling, press, shaper, planner etc..
Lathe
• A lathe is machine tool employed generally to

produce circular objects.
Classification of lathe
• Engine lathe
• Speed lathe
• Turret lathe
• Capstan lathe
• Automatic lathe
• Computer numerically controlled lathe.
Lathe
principle of working
• A lathe works on the principle that “a cutting

tool can remove chips from the rotating work
pieces to produce circular objects”.
• Figure shows a work holding
device known as chuck and is
rotated a very high speed.
• A V-shaped cutting tool is held
against the work piece.
• When the tool is moved parallel
to axis of work piece material is
removed.
Lathe
Major components
• Bed
• Head stock
• Tail stock
• Carriage assembly
• Main drive ( feed mechanism)
• Bed
– It is the foundation part of lathe and supports
all its parts.
– Top of bed has a guide way which is machined
to precision.
• Head stock
– Main spindle projects out from headstock.
– Housing comprises of feed gear box and cone
pulley.
– Rigidly mounted on bed.
• Tail stock
–Movable part of the lathe that carries dead centre.
–Main function is to support the free end of the work
piece.
–Also used to clamp tools like twist drill and reamers
for making holes.
–Tailstock is mounted loosely on guide ways can be
moved and locked in position.
Machine parts
Carriage assembly
• Saddle
• Cross slide
• Compound rest
• Apron
• Tool post
• Saddle
–H shaped casting that slides over the outer set of
guide ways
–Serves as base for cross slide.
• Cross slide
–It is mounted on the saddle.
–Enables lateral movement of cutting tool laterally
by means of cross slide hand wheel.
• Compound rest
–Mounted on top of cross slide and supports the
tool post.
–It can be swiveled at an angle to perform taper
turning operation.
• Tool post
–It is used to clamp the tool holder in position.
• Apron
–It is the part which is fitted saddle, facing
operator.
–It houses levers, hand wheels mechanism for
manual and automatic movement of carriage
assembly.
• Main drive
– It is an electric motor which drives the spindle through
transmission system.
Other component
• Lead screw
– It is a rod which runs longitudinally in front of lathe bed.
– The rotation of lead screw moves the carriage to and fro
longitudinally during thread cutting operation.
Lathe specifications
• Maximum diameter of the workpiece that can be revolved over the lathe
bed.
• Maximum diameter and width of the workpiece that can revolve over
gap in bed.
• Maximum length of workpiece that can be mounted between centers.
• Overall length of the bed.
Size of Lathe
Example: 300 - 1500 Lathe
• Maximum Diameter of Workpiece that can be
machined = SWING (= 300 mm)
• Maximum Length of Workpiece that can be held
between Centers (=1500 mm)
Lathe operations
• Turning
• Taper turning
• Facing
• Thread cutting
• Knurling
• Drilling
• Chamfering
• Parting off
• Grooving etc
Turning
• It is an operation in which
the work piece is reduced
to the cylindrical section of
required diameter.
• Operation is carried out
with a single point cutting
tool.
• Work piece is supported
between the two centers
permit rotation of work
piece.
• Tool is fed perpendicular
to the axis of work piece to
a known depth and then
moved parallel to axis of
work.
Facing
• An operation performed
on lathe to generate flat
surface.
• Direction of feed is
perpendicular to the axis
of the lathe.
• Length of the work should
not be extended more than
1.5 times the diameter of the
work piece.
Knurling
• Operation performed on
lathe to generate serrated
surface.
• Tool used is called as
“knurling tool”.
• Tool consist of one upper
roller and one lower roller
which contains the
impression.
• Tool is set in such a way
that both rollers touch the
work.
• Low speed of about 60 to
80 rpm and feed is 0.38 to
0.78mm/revolution.
Taper Turning
• It is the operation of reducing the diameter of the

workpiece gradually along its length.
Different types of Taper turning
1. Compound slide swivelling method
2. Tailstock offset
Taper Turning by Swiveling the
Compound Rest
• Where D is large diameter of the workpiece, mm
d is small diameter of the workpiece, mm
L is taper length , mm
• Axis of the tool is moved inclined to produce the required
taper.
• Compound rest which supports tool post is swiveled at
required taper angle and locked.
Taper Turning by Tailstock offset
• In this method the workpiece is inclined with respect to the
lathe axis.
• Tool movement is in line with the lathe axis to produce
taper.
• Tail stock is shifted by a small distance called offset.
Thread cutting
• A thread is a helical shaped groove formed on cylindrical
surface of workpiece.
• Thread cutting is an operation performed on lathe to
produce threads by using a tool whose shape will be same
as that of thread.
Drilling
• Drilling is an operation to produce a cylindrical hole in
workpiece.
• Tool used is called as “drill bit”.
• Tool is held on the tailstock and stationary.
• Work is held in chuck.
• Tool is fed against the revolving work by rotating hand
wheel.

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Lathe and Drilling Machines

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Lathe and drilling machines

• It is a process which involves the conversion

• A lathe is machine tool employed generally to

• A lathe works on the principle that “a cutting

• It is the operation of reducing the diameter of the

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