Page 130 - Turner 1st sem Practicals

When layout for a filleted shoulder make allowance for the
radius to be cut. If a filleted shoulder has a 4 mm radius
and 60 mm from the end of the workpiece, the layout should
be 56 mm from the end. This would leave material for cutting
the radius.
Rough and finish turn the small diameter to size.
Mount a radius tool in the holder and set it to centre. Check
the tool bit with a radius gauge to be sure that it has the
correct radius.
Apply a layout dye or chalk to the small diameter as close
as possible to the shoulder location.
Set the lathe spindle speed to approximately one half of
the turning speed. If the radius is too large for a form tool bit, or too much

Start the lathe and bring the tool bit in until it just removes chattering occurs, cut the fillet in steps, using the largest
the layout dye or chalk. radius tool that does not cause chattering. Check the
accuracy of the fillet with a radius gauge. (Fig 8)
Note the reading on the graduated collar of the cross-slide
screw.
Retract the cutting tool by turning the cross-slide handle
anticlockwise one half turn.
Turn the cross-slide handle clockwise until it is within
approximately 1 mm of the original collar setting. The point
of the round nose tool bit should now be about 1 mm away
from the work diameter. This prevents the cutting tool from
undercutting while roughing out the filleted corner.
Turn the carriage hand wheel slowly to start the radius
tool cutting the filleted shoulder. If chattering occurs while
machining the filleted corner, reduce the lathe speed and
apply a cutting fluid to improve the finish of the fillet.
(Fig 6)
Machining an undercut shoulder
Lay out the position of the undercut shoulder along the
length of the workpiece.
Rough and finish turn the small diameter to size.
Mount the undercut tool in the tool-holder and set it to the
centre.
Apply chalk or layout dye to the small diameter as close
as possible to the undercut shoulder location and also on
the face of the larger diameter.
Set the lathe spindle to approximately one half of the turning
speed.
Bring the point of the tool bit in until it just removes the
Continue turning the carriage hand wheel slowly and chalk or layout dye on the face and set the top slide
carefully until the length of the shoulder is correct.
graduated collar to zero.
When stopping the lathe to measure the shoulder distance, Apply a cutting fluid to assist the cutting action and produce
do not move the cutting tool setting by withdrawing it from a good surface finish.
the diameter. (Fig 7)
Retract the cutting tool by turning the cross slide handle
Turn the carriage hand wheel to move the cutting tool away anticlockwise.
from the shoulder slightly.
Repeat the above procedure until the undercut shoulder is
Turn the cross-slide handle anticlockwise about 1 mm machined to the correct depth.
back to the original collar setting.
Bring the tool tip clear off the large diameter face and
Finish the filleted corner by carefully advancing the radius advance the tool axially by 1 division of the top slide.
tool bit with the carriage hand wheel.
Producltion & Manufacturing : Turner - Exercise 1.3.37 117