MILLING MACHINE OPERATIONS - OD1644 - LESSON 1/TASK 1
1
Cause - Failure to take back-off tension on the lead screw after
coming up to the dial indicator reading, causing the table to "creep'; or
failure to lock up the slide ways with the same amount of tension after
moving the table to a new position.
2
Remedy - Take the back-off tension off from the lead screw after
coming up to the indicator reading and lock the table in position.
b.
Plain Milling Machine-knee Type.
(1)
General. The spindle bearings used in the spindle head are the taper
roller type and have been properly adjusted for average conditions before
leaving the factory.
They should not require readjustment before the
machine is to be used. If desired, the end play in the spindle bearings may
be checked after a few months of operation in the following manner: Using a
lead or composition hammer, gently tap the face of the spindle until all of
the play is taken up towards the rear of the machine.
Place a dial
indicator against the face of the spindle, and then tap the spindle shaft
forward from the rear. If the play exceeds 0.001 inch, adjustment may be
made as follows:
CAUTION
Do not attempt to take up the spindle bearings without a thorough
knowledge of the bearing adjustments and the operating
conditions.
(2)
Adjustment.
(a)
Remove the rear cap from the cutter head.
(b)
Loosen the set screws in the bearing head.
(c)
Loosen
or
tighten
the
nut
as
necessary
to
secure
the
desired
adjustment.
(d)
Tighten the set screw and reassemble the rear cap on the cutter
head.
52
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