Page 128 - Turner 1st sem Practicals

Job sequence

TASK 1 : Turning different shoulder

• Hold the job in a four jaw chuck, true and face one • By using the side knife tool, maintain the diameter of
side. 26 mm to a length of 15mm.
• Turn Ø 35mm to the maximum length. Points to remember
• Reverse the job, true, face and maintain total length • Choose the r.p.m. depending upon the diameter.
100mm (Hold about 35mm inside the chuck.)
• Set the tool properly. :
• Reduce the diameter to 32.5 mm up to a length of 55 • Make sure you are getting different shoulders as per
mm.
drawing.
• By using a 1.5mm R radius tool, remove 0.5 mm dia. • Check the steps by using a steel rule. Use sufficient
and turn up to 60mm length as per drawing.
coolant.
• By using a crank tool reduce the diameter to 28 mm to • Remove burrs by filing.
a length of 40mm, including shoulder 2 x 45° as per
drawing.

TASK 2 : Turning under cut

• Hold the job in a four jaw chuck. • After 70mm of length from the face, plunge the under
cutting tool towards the job to make a width of 5mm
• Set the job with the help of surface gauge.
groove maintaining diameter 30mm.
• Set the u/c tool on the tool post to correct centre height.
• Remove the sharp corners.
• Reduce the rpm by 1/3.
• Check the all dimensions.

Skill sequence

Lathe operation - Machining of different types of shoulders

Objectives : This shall help you to
• machine a square shoulder
• machine a bevelled shoulder
• machine a filleted shoulder
• machine an undercut shoulder.

Machining a square shoulder

Face the end of the work to provide a reference surface
point from which to take measurements.
Lay out the position of the shoulder by one of the following
methods.
Make a dot punch mark at the correct distance from the
end of the workpiece. (Fig 1)
Cut a light groove with the point of a sharp tool bit around
the circumference of the work to mark the required length.
(Fig 2)
Rough and finish turn the diameter to within about 1 mm
of the required length.

Mount a facing tool bit in the tool-holder and set it to lathe
axis. (Fig 3)

Producltion & Manufacturing : Turner - Exercise 1.3.37 115