Precision matthews PM-932M Manual

PM-932M Mills with & without power downfeed option
QUILL DOWNFEED
Mills without power downfeed
The quill is controlled in two different ways, coarse and fine.
In the drilling mode, coarse feed, the mill functions like a
standard drill press – lower the quill using any of the three
downfeed levers to rotate the lever hub counter-clockwise. For
milling operations the lever hub is disengaged, and the quill is
controlled by the fine downfeed handwheel. The quill is locked
by a lever on the face of the headstock, Figure 2 (On power
downfeed versions of the PM-932 the quill locking lever is on
the left of the headstock, Figure 2 inset.)
Figure 1 Quill downfeed controls
The lever hub (1) is full-time connected to the quill pinion. The fine
control handwheel (2) is connected by a worm gear to the sleeve (3),
and is free to rotate — doing nothing to the quill — unless it is coupled
to the lever hub (1). Couple sleeve (3) to hub (1) by tightening knob (4).
Coarse feed (Figure 1)
For drilling operations, loosen knob (4), allowing the lever hub
to rotate independently of sleeve (3). If desired, set the depth
stop.
Fine feed (Figure 1)
For milling operations calling for precise, repeatable control
of tool depth, tighten knob (4) to engage the tapered face of
hub (1) with the internal taper on sleeve (3). Tighten the Z-axis
locks.
Rotate the fine control handwheel (2) to raise or lower the quill.
Before switching to fine control, it is usually a good idea to run
the depth stop up to the top. Lower the quill by rotating the fine
control knob clockwise, positioning it precisely either by count-
932 Power downfeed option 4-16-18 V1
Supplement to Section 2 of the PM-932M manual
ing divisions on the graduated dial, or by reference to the front
panel DRO (digital readout). Use the locking lever to hold the
quill firmly in position.
If you are counting divisions be aware of backlash in the worm
drive. This means that the handwheel must always be turn-
ing in the same direction throughout the entire process, from
setting a reference level to subsequent cutting passes at spe-
cific depths – see the backlash discussion in Section 2 of the
manual. Using the DRO – which has no backlash issues – is
less laborious, but remember that the quill is spring-loaded.
This calls for care when releasing the quill locking lever prior
to repositioning the quill downward. If the fine control knob has
been allowed to disengage (backed off counter clockwise), the
quill will jump up by 0.01" or more. To avoid this, make sure
the fine control is firmly clockwise, lightly loading the quill rack,
before releasing the locking lever.
Figure 2 DRO, depth stop & quill locking lever
Above, mills without power downfeed. On PM-932 mills with power
downfeed the quill locking lever is on the left side of the headstock,
inset.
1
Model PM-932M
Depth stop adjust
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