Lower
outer casing of the attachment (guide bush) is kept stationery
by means of torque-bar which should be fixed through the hole
provided in the guide bush and rested against machine column
suitable stay.
Depth of tapping should be adjusted on a drill while tapping
blind holes of limited depth, by raising the machines spindle
the tap automatically reverses at double the tapping speed.
adjustments
is made to the clutch to suit the size of tap being used this
effected by loosening brass screw and rotating cup nut on tap,
thus decreasing or increasing the spring pressure on the clutch.
Numbers are etched on the cup nut to help set the unit to the
desired position for particular size of tap.
it should
however be noted that these adjustment numbers are directive
only for the required pressure on the clutch depends on various
factors like material being tapped, type of threads condition
of taps etc.
the sliding
left and right nuts of the chuck are holdings the tap by gripping
on the flats of its square head. after lightly fixing the tap
between these nuts tighten lower conical jaws by chuck nut with
the help of specially supplied spanner and finally tighten the
upper nuts with the help of alien - head spanner also supplied
with the unit.
oil nipple
for lubrication has been provided in the unit and the unit should
thoroughly be lubricated after about every thousand tapping
operations.
the speed
chart should be gnoe through and the correct speed of the drilling
machine spindle should be maintained a indicated in the chart.
These speeds are only indicative and a slight variation of speed
on lower side, if correct speed is not available should be preferred
to the higher side.
Recommended Tapping Speed For Various Metals
these speeds are approx and intended as a general
guide only, the most effective speed should be determined by
actual test with a given tap, material machine and tapping fluid.
the taps usad should be of high - speed - steel.
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