9
PM 728V-T v2 2020-10
Copyright © 2020 Quality Machine Tools, LLC
HEADSTOCK CONTROLS
Before doing anything, check
the installation instructions in
Section 1
1. Make sure the direction switch is set
to
OFF
. Connect the mill to a 110Vac
outlet.
2. Press and release the green Power
ON
button to energize the control cir-
cuit; the tachometer should light. This
is a self-latching circuit – when the
ON
button is released, a contactor in the
electrical box maintains power until re-
leased by the red
OFF
button (also a
momentary switch).
3. The large red E-stop button is in se-
ries with the
OFF
button. Like the
OFF
button it de-energizes the control cir-
cuit completely, but it should be used
only for emergency disconnect. Once
the E-stop button is pushed in, it stays
in until twisted
firmly clockwise
to re-
lease.
4. The spindle motor is controlled by a
three position switch, Forward/Stop/
Reverse, and a continuously-variable
speed control knob.
FWD
= Forward (clockwise, looking down,
used for most milling and drilling
OFF
= Stop
REV
= Reverse (counter-clockwise, look-
ing down)
Figure 3-2
Belt adjustment
SPINDLE SPEEDS
The PM-728V-T is a belt-driven machine with two speed rang-
es, (
L
) 100-1500 rpm and (
H
) 300-4000 rpm.
To select a speed range, disconnect power, then open the top
cover. Loosen the socket head screws on each side of the
motor, then swing the motor forward to free the belt, Figure
3-2. Make sure that the ribbed belt is properly engaged with
the selected pair of grooved pulleys, then re-tighten. Before
powering up, rotate the spindle by hand to check tracking and
tightness of the belt. Do not over-tighten – aim for ± ¼” slack
between the motor and spindle pulleys.
Excessive cutter noise, chatter, poor finish and tool
wear are often the result of too high a feed rate, and/
or too high a spindle speed. If unsure, go slow!
Section 3 USING THE MILL
Figure 3-1
Headstock controls
Top cover
release
Head tilt
adjust
Fine feed
engage
Drill press
levers
(coarse
feed)
Fine
feed
knob
Quill
DRO
Quill
lock
Spindle
direction
Spindle
speed
Always use the
Direction Switch
, not the
Power buttons, to turn the spindle on and off,
except during an emergency
Use the
Power Buttons
only to power-up
and power-down the mill.
When powering-down, it is normal to hear a
series of beeps from the electrical box.
