Precision matthews PM 728V-T User manual

1
PM 728V-T v2 2020-10 Copyright © 2020 Quality Machine Tools, LLC
Model PM 728V-T Precision Milling Machine
Square column design, heavy cast iron construction
High weight-to-size factor: 370 lb excluding stand
1 HP (750W) brushless dc motor, 110 Vac single phase power
Quiet belt drive, no gears
Variable spindle speed from 100 to 4000 + rpm
Table size 7" x 28"
One-shot lubrication system standard
Quill DRO for precise downfeed measurement
PM-728V-T with optional stand

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PM 728V-T v2 2020-10 Copyright © 2020 Quality Machine Tools, LLC
PM-728V-T
FAQ
R8 collets won’t go
into the spindle
The collet locating screw
could be in too far. Back it
out a little.
My mill doesn’t run
This manual contains essential safety advice on the proper setup, operation, maintenance, and ser-
vice of the PM-728V-T milling machine. Failure to read, understand and follow the manual may result
in property damage or serious personal injury.
There are many alternative ways to install and use a mill. As the owner of the mill you are solely
responsible for its proper installation and safe use. Consider the material contained in this manual
to be advisory only. Quality Machine Tools, LLC cannot be held liable for injury or property damage
during installation or use, or from negligence, improper training, machine modications or misuse.
This manual describes PM-728V-T machines as shipped from early 2020. There may be detail dif-
ferences between your specic machine and the information given here (with little or no impact on
functionality). Please email us if you have questions about any aspect of the manual or your machine
(see our website www.precisionmatthews.com for support contacts). Your feedback is welcomed!
Copyright © 2020 Quality Machine Tools, LLC
This material was originated by Precision Matthews. No portion of the manual may be repro-
duced or distributed in any form without the written approval of Quality Machine Tools, LLC.
The drawbar doesn’t
seem to be long enough
Install the drawbar (1)
INSIDE the spindle cap
(2), as here (unscrew cap,
insert drawbar into spin-
dle, replace cap)
1
2
The control box
beeps when power is
switched o󰀨
110 Vac power connected?
GREEN button pressed?
Speed control set?
E-Stop button out? (pop it out
by twisting rmly clockwise)
Circuit breaker popped?
photo
No problem — this is
not a fault condition

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PM 728V-T v2 2020-10 Copyright © 2020 Quality Machine Tools, LLC
THESE ARE THE MAIN POINTS TO WATCH OUT FOR!
But read the following pages for more information
• Handling the mill is at least a two-person job.
• Lower the center of gravity by hand-cranking the headstock down until the spindle nose
is just clear of the table.
• Lifting gear – sling, hoist or forklift – must be rated for at least 500 lb.
• The working location of the mill must allow: Full left-right travel of the table, also access
to the top of the column (for Z-axis leadscrew maintenance).
• Power requirement is 110V, 60Hz, 1φ, 20A circuit protection.
• Extension cord not to be used
• Before connecting power for the rst time be sure that:
1. The machine is on a rm footing, adequately secured to bench or stand.
2. No chuck or collet is installed.
3. The drawbar has been removed (see below).
4. There are no clamps or locks on moving parts.
5. The speed control knob is set for the lowest speed.
Section 1 INSTALLATION
SETTING UP THE MILL
The PM-728V-T is shipped in two packing cases, one for the machine and tray (and optional 3-axis DRO), one for
the stand, if ordered.
UNCRATING & MOVING THE MILL
The following procedure makes use of an engine hoist, min-
imum weight rating 500 lb. If a hoist is not available, and you
need to use manpower for lifting, see the dismantling instruc-
tions on the following page.
First, no matter what the lifting method is, prepare the bench or
optional stand, with the chip tray in its working location.
Highly recommended! Bolt the bench or stand rmly to the
oor. Check working clearances, Section 2.
1. If the handwheels were shipped loose, install the largest
of the four at the top of the column. The three smaller
handwheels are for the X-axis (2) and Y-axis (1).
2. Release the table locks, X-axis and Y-axis.
3. Release the headstock Z-axis locks.
4. Center the table (X-axis), then move the table back to the
column as far as it will go (Y-axis).
5. Crank the headstock (Z-axis) down so that the spindle
nose is just clear of the table. The mill’s center of gravity
should now be as far down and back as possible. Tight-
en the Z-axis lock.
6. Unscrew the four nuts securing the mill to the pallet.
7. If necessary, setup the hoist with its legs straddling the
machine as follows: 1. Remove one leg from the hoist,
then position the other leg over the pallet, as close to
the machine base as possible. 2. Re-install the removed
leg, positioning it over the pallet, likewise close to the
machine base. 3. Set the hoist arm short enough so that
the hook is immediately overhead the collar.
8. Run a padded sling under the headstock, as Figure 1-2.
9. Taking care not to damage the Z-axis locking handle
and the electrical box, hook the sling, basket style, to the
hoist's hook/chain.
Figure 1-1 Access to the drawbar
Removing the drawbar
1. With the table protected by scrap material, loosen the
quill lock lever, then lower the quill.
2. Swing open the drive cover in front of the motor, Figure
1-1.
3. While holding the spindle nose with the special C-wrench
(supplied), use a 17 mm wrench to unscrew and remove
the spindle cap. See also Figures 3-3 and 3-4.
4. Remove the drawbar from the spindle. Re-install the spin-
dle cap, hand-tight.
Return
spring
cup
Spindle
cap
Drawbar

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PM 728V-T v2 2020-10 Copyright © 2020 Quality Machine Tools, LLC
OPTIONAL
PARTIAL DISASSEMBLY OF THE MILL
If a hoist is not available, and the mill has to be moved by man-
power, this is more manageable if the headstock and table are
temporarily removed. Not a one-person procedure.
Table removal
1. Remove handwheels, support brackets and other compo-
nents from both ends of the leadscrew. Set the parts aside
in separate left-hand/right-hand containers.
2. Remove the gib from the front dovetail.
3. Slide table to one side then lift it clear, taking care not to
damage the dovetails.
Figure 1-3 Lowering the mill into position
Figure 1-4 Removing the headstock
Inset: Use a telescoping magnetic pickup
tool to retrieve/reposition T-bolts
Headstock removal
1. Assemble a stack of 2 x 4s as Figure 1-4. Lower and lock
the quill so that the spindle nose rests on the front 2 x 4
(this is for balance, not for load bearing).
2. Crank the headstock down to the point where the head-
stock is felt to be pressing rmly on the back 2 x 4s —
rmly,meaning the headstock will not suddenly shift
when its two attachment nuts are loosened.
3. With another person on hand to stabilize the headstock,
remove the two attachment nuts, then move the table for-
ward clear of the T-bolts.
Figure 1-2 Sling position
Z-axis
lock
10. Slowly lift the mill clear of the pallet.
11. Roll the mill into position over the chip tray, then lower it
into place, Figure 1-3.
12. Secure the mill to the bench or stand. If this is a stand in-
stallation, use the four bolts M8 x 100 mm bolts supplied.
Use plain and lock washers in all locations.

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PM 728V-T v2 2020-10 Copyright © 2020 Quality Machine Tools, LLC
INITIAL CHECKS
Read Section 3 if unsure about any item in the following
1. Check that no chuck or collet is installed, drawbar re-
moved; no clamps or locks on moving parts.
2. Turn the speed control knob fully counter-clockwise (low-
est speed).
3. Open the blue motor cover. Make sure the belt is set for
low speed (belt running on the larger front pulley.) If not,
re-position the belt, Figure 3-2. Replace the motor cover.
Make sure the spindle is free to turn.
4. Connect 110 Vac power.
5. Be sure the E-Stop (Emergency) button has not been
pushed in (it should pop out when twisted rmly clock-
wise).
6. Press the green Power button. The power lamp and the
tach display should light.
7. Select FWD spindle direction, then turn the speed knob a
few degrees to the right. Viewed from above, the spindle
should rotate clockwise.
8. Rotate the speed control knob clockwise for a speed of
300 to 400 rpm. Run the spindle at that speed for about
1 minute, then progressively increase the speed to the
maximum (about 1500 rpm).
9. Check the emergency function by pressing the E-Stop
button. This should disable the power circuit, stopping the
spindle. You will hear a series of beeps from the electrical
box once power is disconnected. This is normal.
If #8 doesn’t happen, the E-stop function is defective,
and needs attention - This should stop the machine when
presses
10. Restore power by twisting the E-Stop button rmly to the
right; this will cause it to pop out. You can now re-start the
machine as shown starting in step 6 above.
11. Re-install the drawbar UNDER the spindle cap, Figure
1-1.
Assembly and cleanup
Unnished metal surfaces may be protected in shipping by
thick grease and/or paper. Carefully remove these using a
plastic paint scraper, disposable rags and a light-oil such as
WD-40. Coat bright machined surfaces after cleaning with a
rust preventative such as Rustlick. Do not leave them bare, or
rust may stary quickly.
Level the mill using the table surface for reference, shimming
under the tray if necessary. If the mill is on the optional stand,
adjust the leveling feet. Oil the ways and leadscrews (Z-axis
leadscrew excepted, inaccessible).

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PM 728V-T v2 2020-10 Copyright © 2020 Quality Machine Tools, LLC
Section 2 FEATURES & SPECIFICATIONS
MODEL PM-728V-T Milling Machine
General information
The PM-728V-T is a robust “square column” mill with R8 spindle and continuously-variable spindle speed up to 4000 rpm. It is
designed for day-in, day-out use in the model shop. With a weight of 370 lbs it can handle far more than the typical machine of its
size. For precise control of cutter depth there is a worm-driven quill downfeed with graduated dial and built-in DRO, completely
independent of headstock elevation.
The reversible spindle runs in high-quality, deep-groove ball bearings enclosed in a robust quill with coarse (drilling) and ne
(milling) downfeed options. It is powered by a 1 HP (750 W) brushless dc motor. Spindle speed is continuously variable from
approximately 100 to 1500 rpm, low range, and 300 to 4000 rpm, high range. This is a gearless design with two-step pulleys on
motor and spindle coupled by a long-life ribbed belt. The headstock can be tilted 90oclockwise and counter-clockwise from the
vertical. Precision ground dovetailed ways for table and headstock ensure smooth, precise motion in all three axes: X = left/right
motion of table 19 in., Y = front/back motion of table 10 in., Z = headstock up/down, 16-1/4 in. (Installation of DRO scales on the
table and headstock may limit these numbers.)
PM-728V-T dimensions
41 30
32
76-1/2"
max
34-3/4
8-1/2"
3-1/4"
44-1/2"
max

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PM 728V-T v2 2020-10 Copyright © 2020 Quality Machine Tools, LLC
PM-728V-T SPECIFICATIONS
Special accessory supplied:
Spindle C-wrench
Power requirement 110V, 60Hz single phase, 20A circuit
Approximate weight Machine only: 370 lb net, 450 lb shipping
Optional stand: 100 lb net, 110 lb shipping
General
Machine height, no stand Normal operations: 36 in.
Head at max elevation: 44-1/2 in.
Machine height, mounted on stand Normal operations: 67-1/2 in.
Head at max elevation: 76-1/2 in.
Stand dimensions Height, oor to chip pan surface: 31-1/2 in.
Chip pan: 21-1/2 in. W x 24-3/4 in. D
Footprint: 21 in. W x 20-1/2 in. D
Floor space required Width, full left-right travel of table: 62 in.
Depth, Y-axis handle tip to back of chip
pan: 30 in.
Dimensions
Table
Table size 7 x 28 in.
Front-back travel, Y-axis With DRO
With full way-support: 7-3/4 in.
Between hard stops: 9-1/2 in.
No DRO
8-1/2 in.
10 in.
Left-right travel, X-axis With full way-support: 17-3/4 in.
Between hard stops: 19 in.
Leadscrew pitch, both axes 10 TPI (0.1 in. per turn)
Handwheel dials, both axes 0.001 in. graduations
T-slots (3) Width: 12 mm (use PM 1/2 in. clamp kit)
Between Slots: 55 mm (approx. 2-5/32 in.)
Maximum load, centered 300 lb
Motor & Headstock
Motor 1 HP brushless dc, variable speed
Spindle speed Continuously variable, 100 to 4000 rpm
in two ranges
Spindle dimensions Internal taper: R8
Drawbar: 7/16-20, 11 mm hex wrench
Top end splines (6): 22 mm OD
Quill (spindle) travel 3 in.
Spindle nose to table Zero to 16-1/4 in.
Spindle centerline to front face of column 8-3/4 in.
Z-axis leadscrew pitch 10 TPI, 0.001 in. dial graduations
Headstock vertical travel 16-1/4 in.
Headstock left-right tilt 90 degrees - zero - 90 degrees
Typical cutting capacities in steel
Drilling 3/4 in., End milling 1 in., Face milling (with multi-tip tool) 3 in.
T-slot dimensions

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PM 728V-T v2 2020-10 Copyright © 2020 Quality Machine Tools, LLC
Everyday precautions
• This machine is designed for milling and drilling operations by experienced
users familiar with metal-working hazards.
• Untrained or unsupervised operators risk serious injury.
• Wear ANSI-approved full-face or eye protection at all times when using the
machine (everyday eyeglasses are not reliable protection against ying particles).
• Wear proper apparel and non-slip footwear – be sure to prevent hair, clothing
or jewelry from becoming entangled in moving parts. Gloves – including tight-t-
ting disposables – can be hazardous!
• Be sure the work area is properly lit.
• Never leave chuck keys, wrenches or other loose tools on the machine.
• Be sure the workpiece and machine ways are secure before commencing mill-
ing or drilling – hold-downs and/or vise fully tightened, X-Y-Z axes locked, cutting
tool secured.
• Use moderation: light cuts, low spindle speeds and slow table motion give
better, safer results than “hogging”.
• Don’t try to stop a moving spindle by hand – allow it to stop on its own.
• Disconnect 110V power from the mill before maintenance operations such as
oiling or adjustments.
• Maintain the machine with care – check lubrication and adjustments daily
before use.
• Clean the machine routinely – remove chips by brush or vacuum, not com-
pressed air (which can force debris into the ways).
No list of precautions can cover everything.
You cannot be too careful!

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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 rmly 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 nish 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 o󰀨,
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.

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PM 728V-T v2 2020-10 Copyright © 2020 Quality Machine Tools, LLC
Two tools are required to install or remove R8 tooling: an 11 mm
wrench for the square drawbar nut, and the supplied C-wrench
which engages in ats at the bottom end of the spindle.
Figure 3-5 Two-step belt drive
The drawbar collar, Figure 3-2, must be
UNDER the spindle cap, as shown
Removing R8 tooling
Protect the table, vise or workpiece under the spindle with rags
or scrap wood. Why? Because they can easily be damaged by
falling tools and drill chucks. The cutting tool itself can also be
damaged in the same way.
Lock the spindle with the C-wrench, loosen the drawbar one
turn or less, just enough to unseat the taper, then tap the top
of the drawbar with a brass or dead-blow hammer to break the
taper seal. Unscrew the drawbar with one hand while support-
ing the R-8 device with the other hand.
R8 tooling is located in the spindle bore by an M4 x 6 mm
long set screw. If it is dicult or impossible to insert the
R8 device, chances are the set screw is in too far. Rotate
the spindle by hand to expose the screw, Figure 3-6, then
back it out a fraction of a turn using a 2 mm hex wrench.
Hand rotate the spindle again to check that the screw
clears the inside surface of the quill.
INSTALLING AND REMOVING TOOLING
The spindle and drawbar are designed for R-8 taper collets,
drill chucks and other arbors with the standard 7/16”-20 inter-
nal thread.
Figure 3-4 Spindle disassembled (drawbar omitted)
Figure 3-3 Spindle schematic
Return
spring
cup
Spindle
cap
Drawbar
Figure 3-6 Collet set screw
Installing R8 tooling
Install the R-8 device, then hand-thread the drawbar into it until
the drawbar collar bottoms on the splined spindle (on the ma-
chine itself this action is concealed by the spindle cap, Figure
3-3). Fully tighten the drawbar with an 11 mm wrench, while at
the same time holding the spindle stationary with the special
C-wrench, page 7. [Do NOT try to hold the spindle using the
ats on the spindle cap.]

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PM 728V-T v2 2020-10 Copyright © 2020 Quality Machine Tools, LLC
MOVING THE TABLE & HEADSTOCK
Conventionally, left-right movement of the table is said to be
along the X-axis (also called “longitudinal travel” or “travers-
ing”). Leadscrew handwheels are provided at both ends of the
table, Figure 3-7. Front-to-back movement is along the Y-axis,
sometimes called “cross travel”. The Y axis leadscrew has a
single handwheel at the front, Figure 3-8.
Headstock motion is in the Z-axis, in line with the vertical col-
umn. The headstock is raised and lowered by a handwheel at
top right of the column, Figure 3-9.
Figure 3-10 X-axis locks
Figure 3-11 Y-axis lock
When possible, operations calling for precise
depth control (such as milling) should be done
with the headstock locked, also with the quill
fully retracted into the headstock and locked.
Figure 3-12 Z-axis lock (1)
Also shown here (2) is one of two headstock attachment nuts.
Figure 3-7 X-axis handwheel & dial (right hand)
Figure 3-8 Y-axis handwheel & dial
Figure 3-9 Z-axis handwheel & dial
LOCKING THE AXES
Before machining a workpiece it is usually necessary to po-
sition the table precisely, then lock either the X or the Y axis,
sometimes both (for drilling and similar operations). You can
also use the lock levers to apply a light drag to the axis in
motion. This can help reduce chattering (better surface nish)
and also lessen the chance of overshooting inadvertently. To
reduce wear, free the levers once the operation is completed.
Each axis has a leadscrew with handwheel and graduated dial
with 0.001” divisions, 0.1” per revolution, Figures 3-7 to 3-9.
If the mill is not equipped with digital readouts (DROs), the
table and headstock can be accurately positioned by count-
ing whole turns and divisions, keeping leadscrew backlash
in mind. This means that motion must always be in the same
direction up to the point of reference, then on to the desired
location, see “Positioning by Counting X-Y Divisions”, later in
this section.
2
1

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PM 728V-T v2 2020-10 Copyright © 2020 Quality Machine Tools, LLC
POSITIONING BY COUNTING X / Y DIVISIONS
QUILL DOWNFEED
The quill is controlled in two di󰀨erent ways, coarse and ne.
For drilling operations, coarse feed, the milling machine oper-
ates like a standard drill press with a 3-lever hub. Lever action
lowers or raises the quill in the usual way by rack and pinion.
Return action is assisted by a compression spring within the
quill and spindle assembly, Figures 3-3 and 3-4.
For milling operations the lever hub is not usually rotated by
lever action. Instead it is driven through worm gears turned by
the ne control knob, Figure 3-13 (2). This allows the quill to be
driven precisely to any desired position. The ne control knob,
because it drives through a worm, cannot be back-driven by
return-spring action on the quill (in other words, it stays where
it’s put). For milling operations the quill should, when possible,
be fully retracted, then locked by the lever on the left of the
headstock, Figure 3-1.
Coarse feed (Figure 3-13)
For drilling operations, loosen knob (4), allowing the lever hub
(1) to rotate independently of sleeve (3).
Fine feed (Figure 3-13)
For milling operations calling for precise, repeatable control of
tool depth, tighten knob (4) to engage hub (1) with the internal
taper on sleeve (3). Tighten the Z-axis lock, Figure 3-12.
Rotate the ne control knob (2) to raise or lower the quill. Low-
er the quill by rotating the ne control knob clockwise, position-
ing it precisely either by counting divisions on the graduated
dial, or by reference to the quill digital readout (DRO), Figure
3-1. Use the locking lever left of the headstock to hold the quill
rmly in position.
Figure 3-13 Quill downfeed controls
The lever hub (1) is connected at all times to the quill pinion, which
engages a rack on the back side of the quill. The ne control knob (2)
drives sleeve (3) through a worm gear. If clamp knob (4) is unscrewed,
both (2) and (3) rotate freely, doing nothing to the quill. Fine feed is
engaged by tightening knob (4) to clamp (3) and (1) together. The
depth dial, graduated in 40 mil (0.04") increments, is locked to sleeve
(3) by thumbscrew (5).
Worm shaft (6) enables precise adjustment of the headstock tilt angle.
The quill DRO – which has no backlash issues – o󰀨ers a less
laborious way of setting tool height, but bear in mind that the
quill is spring-loaded.
This calls for care when releasing the quill locking lever. If the
ne control knob has been allowed to disengage (backed o󰀨
counter clockwise), the quill may jump up by 0.01” or more. To
avoid this, make sure the ne control has been turned clock-
wise to apply downward pressure on the quill before the lock-
ing lever is released.
If you are counting downfeed divisions be
aware of backlash in the worm drive.
QUILL DRO
The quill DRO is in metric mode when switched on. Press
the mm/in button to display inches.
Replace the battery by removing the small molded cover
on the face of the DRO unit (align the dots). Check the
type number and voltage of the installed battery. Replace
with an equivalent (LR44) silver oxide cell available from
local retailers.
14
2
3
5
Switch o the DRO when not in use!
Figure 3-14
Quill depth dial
6
For all spindle positioning operations avoid using the
quill lock. When possible, retract the quill fully, then
adjust the headstock elevation instead.
Why? On practically all vertical mills, including the heavier
knee mills, locking the quill may o󰀨set the spindle by a few
thousandths of an inch. For milling operations this is not a
problem provided edge "nding" and subsequent machining
are both done with the quill retracted and locked.
Drilling, on the other hand, is quite di󰀨erent. If the edge of the
workpiece has been “found” with the quill locked, this may af-
fect placement of holes drilled thereafter. Instead, do the nd-
ing by lowering the headstock, or lower the quill with the ne
downfeed control — no locking in either case.

13
PM 728V-T v2 2020-10 Copyright © 2020 Quality Machine Tools, LLC
Figure 3-15 Workpiece positioning example
TAPPING OPERATIONS
When threading a drilled hole it is essential to align the thread-
ing tap properly in the bore. The mill is often used for this
purpose, ideally with a dedicated (non-slip) tap holder or, for
production work, an auto-reverse tapping attachment, e.g.,
Tapmatic.
A drill chuck can be used instead for sizes up to (say) M6 or
1/4”, beyond which the chuck may not grip tightly enough to
avoid slippage. Tapping can be done under power, or by hand
turning the chuck.
For either method, it is essential to use a tapping uid. Any cut-
ting oil is better than none, but most users nd Castrol’s Moly
Dee the most reliable for threading in steel.
If power tapping, bear in mind that the spindle does not stop
instantaneously, so be careful tapping blind holes. Free the
quill locking lever. Start with the lowest spindle speed. Coun-
teract the e󰀨ect of the quill's return spring by applying gentle
downward pressure on the quill while feeding in the tap. (This
is to reduce lifting force on the workpiece, which tends to pull
the workpiece out of the chuck.) For easier tapping it may be
helpful to experiment with a larger hole than specied in the
In this illustration a hole is to be drilled exactly 0.25” on the
Y-axis relative to the front edge of a workpiece in a vise, or
otherwise clamped to the table, Figure 3-15.
1. Install an edge-nder in collet or chuck (a tip diameter of
0.2” is assumed).
2. Lock the X-axis (optional).
3. If the reference edge is already to the back the spindle
centerline, do nothing; if not, rotate the Y-axis handwheel
clockwise to send the workpiece backwards (toward the
column).
4. Engage the ne downfeed, Figure 3-13.
5. With the spindle running, lower the quill as necessary
using the ne downfeed control, then bring the table for-
ward (counter-clockwise), stopping at the point where the
edge-nder just makes contact (the tip jumps out of line).
Stop the spindle.
6. While holding the Y-axis handwheel to prevent rotation,
zero the Y dial.
7. Raise the quill, then rotate the handwheel one exact full
turn counter-clockwise (0.1”) to bring the reference edge
to the spindle centerline.
8. Rotate the handwheel 2-1/2 turns counter-clockwise to
bring 50 on the dial opposite the datum; the spindle is now
precisely 0.25” to the back of the reference edge.
TILTING THE HEADSTOCK
In routine operations the user relies on squareness of the spin-
dle relative to both axes of the table. Front-to-back squareness
is set at the factory, and is not adjustable by everyday meth-
ods. In the other plane, the headstock can be set to any angle
up to 90 degrees either side of the normal vertical position.
Because re-establishing true vertical (tramming) on any mill is
a time consuming process, most machinists look rst for other
ways of handling a project instead of tilting the head.
The headstock is secured by two nuts spaced on either side,
Figure 3-12. The headstock is top-heavy, and may swing sud-
denly to either side unless a helper is on hand to restrain it.
Testing for movability as you go, carefully loosen the nuts by
degrees. Be especially careful if the head has not been moved
before — the paint seal may let go without warning. (First-time
tilting may also call for unusual e󰀨ort on the wrench.)
Set the headstock to the desired tilt using a digital angle indi-
cator such as Figure 3-16. Insert a length of bar stock, ideally
ground, in a collet of known accuracy (check for runout at the
tip). Angle indicators like this are typically good within ± 0.2o. If
the project calls for greater accuracy a more accurate means
of angle measurement will be needed.
Fine adjustment of tilt angle is made easier by a worm shaft
& worm wheel combination. The worm shaft, Figure 3-13 (6),
engages a worm wheel secured to the headstock casting, Fig-
ure 3-17 inset. Use a 21 mm wrench to turn the worm shaft.
Figure 3-16 Headstock tilt angle measurement
Use the indicator's relative mode to measure the angle
between the spindle and the surface of the workpiece.
usual tap drill charts. Typically, a 10% reduction in drill size
below nominal causes no real di󰀨erence in holding power or
thread integrity under load.
Figure 3-17 Headstock worm wheel

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PM 728V-T v2 2020-10 Copyright © 2020 Quality Machine Tools, LLC
TRAMMING THE HEADSTOCK
As shipped, the mill is set to zero tilt, squared accurately
enough for initial test drillings, etc., out of the crate For more
demanding project work thereafter, the spindle needs to be
set at precisely 90 degrees relative to the table, in other words
trammed. “Out of tram” may show up as an o󰀨set of a few
thousandths between entry and exit of a deep hole, or as a
scalloped e󰀨ect when surfacing a workpiece with a large-radi-
us y cutter, greatly exaggerated in Figure 3-18.
Tramming is done by ne-tuning the headstock tilt angle.
Check the tram by attaching a dial indicator to some form of
“sweepable” holder installed in the spindle. The aim is to adjust
tilt for the same reading on either side of the X axis. The longer
the radius arm, the greater the sensitivity.
Figure 3-19 shows a typical shop-made holder; it has a thread-
ed arbor allowing the choice of two radius arms, 6 and 10 inch-
es measured from spindle centerline to indicator tip. A collet
is used to hold the arbor, in this example 5/8” diameter. The
dimensions are arbitrary, but note that the indicator must be
rmly attached, with the arm rock-solid relative to the indicator
spring force (which can be considerable on plunger-type indi-
cators).
A suggested procedure for establishing tram:
1. Disconnect power.
2. Install the dial indicator.
3. If the headstock has been tilted, reset it to the approximate
zero degree position on the tilt scale, then tighten the two
nuts enough to avoid unexpected headstock movement.
4. Remove the vise, if installed, and clean the table surface.
If there are noticeable grooves or dings, atten the surface
with a diamond lap or ne-grit stone.
5. Set a 1-2-3 block (or other precision-ground block) on the
table under the indicator probe.
6. Switch on the quill DRO.
7. Using the ne downfeed lower the spindle to give an indi-
cator reading of about half-scale.
8. Note the dial indicator and DRO readings, then back o󰀨
the ne downfeed at least a couple of turns to avoid colli-
sion when sweeping.
9. Reposition the 1-2-3 block to the opposite location on the
table.
Figure 3-19 Shop-made indicator holder
Tramming calls for patience! Expect to tighten and
re-check several times (simply tightening the head-
stock attachment nuts can itself aect the tram)
A similar procedure may be used to check tram in the Y-axis,
front to back. Tram error in the Y-axis may show up as a scal-
loping e󰀨ect when y cutting a nominally at surface, Figure
3-18, red hashed line. Y-axis tram is established in manufac-
ture, and should be adequate for most purposes.
If more precise tram is called for, it can be adjusted by sand-
wiching a metal shim between the headstock and its sliding
base (saddle) on the column. It is more likely that the head-
stock is nodding forward rather than leaning backward, so start
with (say) a 1 mil (0.001") shim in the bottom quadrant of the
machined mating surfaces between headstock and saddle.
This is a temporary x that may not be satisfactory if the head-
stock is subsequently rotated.
10. Swing the indicator holder to the new location, then lower
the spindle – ne downfeed again – to give the same dial
indicator reading as in step (8).
If the headstock is perfectly trammed – highly unlikely at the
rst shot – the DRO reading should be as in step (8). If not,
loosen the nuts just enough to allow the headstock to allow
very small adjustments — fractions of a degree — by turning
the worm shaft, Figure 3-13 (6). Re-tighten the nuts.
Repeat steps (7) through (10) until satised with the tram,
tightening the nuts as you go. This will likely call for several
iterations. There is no “right” tram; the acceptable di󰀨erence in
side-to-side readings depends on project specs. As a starting
point, aim for ± 0.002” with a sweep radius of 5 or 6 inches.
Figure 3-18 Head tilt a󰀨ects surface atness
This is the e󰀨ect, much exaggerated, if the head is tilted minutely out
of square when milling a surface with a large diameter cutter. In the
other axis the scalloping e󰀨ect would be at right angles (hashed red
line) if the head is tilted forward or back, and the table is moved in the
Y-axis.
In all bench mills there is a tendency for Y-axis tram to
vary minutely as the headstock elevation is changed
— select the "most used zone" when shimming

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PM 728V-T v2 2020-10 Copyright © 2020 Quality Machine Tools, LLC
VISE KEYS
Most precision vises come with key slots on the underside ma-
chined exactly parallel to the xed jaw. Key slots, Figure 3-21,
can be a great time saver. Properly installed they allow the
vise to be removed and replaced routinely, accurately enough
for general machining without the need for indicating every
time.
Most 4” vises have either 14 mm or 16 mm slots, calling for
shop-made T-shape adapter keys as Figure 3-22. It is well
worth the e󰀨ort to make these precisely. Aim for a snug t in
both vise and table, but not so tight that it takes more than a
small amount of e󰀨ort to lift the vise clear. Case hardening is
recommended, with nal tting using a ne stone or diamond
stone.
INSTALLING & INDICATING A VISE
For routine milling operations the workpiece is held in a preci-
sion vise. For the PM-728V-T a 4” vise is most suitable.
“Indicating” means checking the alignment of the xed (back)
vise jaw relative to the axis of table motion.
Install the T-bolts and align the vise by eye. With one of the
clamp nuts snug, but not tight, tighten the other one just short
of fully-tight (but tight enough so the vise won’t budge without
a denite tap from a dead-blow mallet).
A typical setup for indicating is shown in Figure 3-20. There is
no spindle lock, but you need to make sure that the spindle
does not rotate throughout the procedure — it helps if the low
spindle speed is selected.
Set the indicator tip against the upper edge of a precision ref-
erence bar or, if not available, use the front face of the xed
jaw of the vise instead (check for dings, hone if necessary).
Adjust the Y-axis to pre-load the indicator to mid range at the
tightly-clamped side of the vise, then lock the Y-axis.
Note the indicator reading, then watch the indicator as you
traverse the table slowly toward the loosely clamped side —
watch for any sign of spindle rotation. Ideally, there should
be no discrepancy between the indicator readings at the two
ends — unlikely at the rst attempt. Return the table to the
starting point, then repeat the process, tapping the vise in as
you go. Repeat the process as often as necessary for the de-
sired accuracy, progressively tightening the “looser” nut. Now
fully tighten both nuts, and re-check again (tightening a nut
can itself introduce signicant error). An established routine
like this – tight to loose – can save a lot of time.
Most users aim for an end-to-end di󰀨erence of not more than
± 0.001” over the width of the vise jaw.
Figure 3-22 Shop-made vise key
Dimensions in millimeters
Figure 3-21 Vise keys installed on X-axis
On most vises the keys can also be installed on the long axis.
Figure 3-20 Indicating the vise
The tip of a standard dial indicator, arrowed, rides along the side face
of a ground reference bar (or the front face of the back jaw).

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PM 728V-T v2 2020-10 Copyright © 2020 Quality Machine Tools, LLC
Figure 4-1 Gib adjustment, X and Y axes
The left adjustment screw for the X axis is in a similar location to (1)
on the left side of the saddle casting. The back adjustment screw for
the Y axis gib (2) is under the solid rubber way cover behind the table.
Section 4 MAINTENANCE
Unplug the 110V power cord before any
maintenance operation!
RECOMMENDED LUBRICANTS
One-shot oiler: ISO 68 way oil, such as Mobil Vactra No. 2,
or equivalent
Visible gears such as quill rack and pinion, Z-axis bevel
gears: light general purpose grease, NLGI No. 2, or equiva-
lent
X, Y and Z leadscrews: ISO 68 way oil, Vactra No. 2, or
equivalent
General lubrication of parts not one-shot oiled: General
purpose ISO 68 way oil
GENERAL OILING
Assuming a clean environment – no abrasive particles or ma-
chining debris – lack of proper lubrication is the main cause of
premature wear. There should a small amount of seepage of
oil from the mating surfaces lubricated by the one-shot oiler,
namely the X, Y and Z dovetails. Be concerned if no seepage
is visible.
A high-pressure air line can force sharp particles into the gaps
between machine ways, and is not recommended for removing
debris. Brushing o󰀨 with a disposable paint brush is preferred.
Operate the one-shot oiler every few hours of operation. Use
a dedicated short-bristle brush to apply oil to the leadscrews,
and to the visible portions of the quill rack and pinion.
Remove all machining debris and foreign objects
before lubricating ANYTHING! If need be, any oil is
better than no oil – but use the recommended lubri-
cants when you can.
GIB ADJUSTMENT
Gibs on the X, Y and Z axes control the t of the mating dove-
tailed surfaces. They are gently-tapered lengths of ground cast
iron located by opposing screws at each end. Adjusting them is
a trial and error process that takes time and patience. Aim for
the best compromise between rigidity and reasonably free ta-
2
1
ble movement. Too tight means accelerated wear on the ways
and leadscrews. Too free means workpiece instability, inaccu-
racies and chatter.
Both screw heads must be tight against the gib ends. If you
loosen one, tighten the other. Remove the way covers for ac-
cess to the back of the Y gib and bottom of the Z gib.
Figure 4-2 Z-axis gib adjustment, upper screw
The lower screw is under the solid rubber way cover.
LEADSCREW BACKLASH CORRECTION
When alternating between clockwise and counter clockwise ro-
tation of the X or Y leadscrews, the handwheel moves freely a
few degrees but the table stays put. This is backlash, a feature
of all leadscrews other than the precision type found on CNC
machines. The acceptable amount of lost motion depends on
the user, but between 0.005” and 0.010" is generally a good
compromise. Smaller numbers are possible, but overdoing it
can lead to premature wear of leadscrew and nut.
Excessive backlash can be corrected by compressing the
leadscrew split nut. For the X-axis this is done by tightening
the socket head screw in Figure 4-3. Use a long-handled 4 mm
hex wrench, or (better) a multi-tool with a 4 mm insert.
Figure 4-3 Table (X-axis) leadscrew nut adjustment
Table removed for visibility. The screw is accessible from the
left side with a long-handled 4 mm hex wrench. Also seen in
this photo are machined oil grooves fed by the one-shot oiler.

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PM 728V-T v2 2020-10 Copyright © 2020 Quality Machine Tools, LLC
The corresponding adjustment for the Y-axis is shown in Fig-
ure 4-4.
Figure 4-4 Y-axis leadscrew nut adjustment
Use a ratcheting wrench with a 4 mm hex insert.
DOWNFEED RETURN SPRING
The quill should automatically retract when the coarse down-
feed levers are released following a drilling operation. If it does
not, check for binding in the quill lock. The return spring, Figure
4-7, is held by a spring cup which is locked to the spindle by
a special C-clip beneath the spindle cap, Figure 4-6. Spring
force is not adjustable.
Figure 4-6 Removing the special C-clip
SERVICING QUILL & SPINDLE
In the normal use the quill assembly needs only oiling on
its sliding surface. The spindle runs on pre-lubricated deep-
groove ball bearings and needs no routine attention. If the
bearings need to be serviced or replaced, remove the quill/
spindle assembly as follows:
IMPORTANT: Use wood blocks or other means to protect the
table, and to prevent unexpected downward movement of
the quill assembly.
1. Remove any installed R8 device from the spindle.
2. Lock the spindle with the C-wrench, then unscrew the spin-
dle cap (17 mm ats) from the spindle.
3. Remove the drawbar.
4. Press down on the return spring cup while removing the
C-Clip, Figure 4-6.
5. Remove the return spring, Figure 4-7.
6. Using a 2.5 mm hex key remove the two button head
screws securing the DRO scale and stand-o󰀨 block to the
quill assembly.
7. Loosen the quill lock lever, then remove the quill assembly
from the headstock.
For access to the leadscrew nut, remove the two screws se-
curing the ange casting at the front. Unscrew the leadscrew,
then slide the saddle/table assembly forward as in Figure 4-5.
Figure 4-5 Withdrawing the Y-axis leadscrew
Return
spring cup
Spindle
cap
Figure 4-7 Quill return spring

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PM 728V-T v2 2020-10 Copyright © 2020 Quality Machine Tools, LLC
Model PM-728V-T Electrical Fig 1
Section 5 PARTS
Short beeps Possible cause
Series of beeps after
pressing stop, or dis-
connecting power
Powering-down, nor-
mal operation
Two beeps Low voltage (motor is
running)
Three beeps Overload
Four beeps Over-heating
Five beeps Over-voltage
Six beeps Over-current
Seven beeps EEPROM error
WARNINGS
Long beeps Possible cause Note
Two beeps Bus voltage is lower
than 250Vdc
F_058=250.0
Three beeps Output current is
higher than 7A
F_056 =7.0
Four beeps Drive temperature is
higher than 80 ° C
F_057=80.0
There may be detail dierences
between this representative drawing
and the machine as supplied

19
PM 728V-T v2 2020-10 Copyright © 2020 Quality Machine Tools, LLC
Model PM-728V-T HEADSTOCK & SPINDLE Fig 2
There may be detail dierences
between this representative drawing
and the machine as supplied

20
PM 728V-T v2 2020-10 Copyright © 2020 Quality Machine Tools, LLC
Ref Description Part
1 Spindle cap Z5962
2 Draw bar Z5963
3 C-clip, spring cup retainer Z5964
4 Return spring cup Z5965
5 Return spring Z5966
6 Front plate Z5967
7 Spindle pulley Z5968
8 Bearing 6209ZZ Z5969
9 Spindle sleeve Z5970
10 Tach disk Z5971
11 Ball bearing 6007ZZ Z5972
12 Lock lever Z5973
13 DRO bracket Z5974
14 Sensor Z5975
15 Pin Z5976
16 Worm shaft Z5977
17 Knob Z5978
18 DRO back plate Z5979
19 DRO assembly Z5980
20 Scale bracket Z5981
21 Motor Z5982
22 Motor pulley Z5983
23 Belt Z5984
24 Motor base Z5985
25 Head casting Z5986
26 Set screw Z5987
27 Head tilting worm shaft Z5988
28 Pinion shaft Z5989
29 Worm wheel Z5990
30 Flange Z5991
31 Dial Z5992
32 Leaf spring Z5993
33 Clamp knob Z5994
34 Lever knob Z5995
35 Handle lever Z5996
36 Pinion shaft hub Z5997
37 O-ring Z5998
38 Spindle spline block Z5999
Ref Description Part
39 Ball bearing 6005ZZ Z6000
40 Quill Z6001
41 Bearing spacer Z6002
42 Ball bearing 7007 Z6003
43 Spindle Z6004
44 Bearing cover Z6005
45 Drawbar cover Z6006
47 Drive cover Z6007
48 Drive rear cover Z6008
49 Clamp screw Z6009
50 Clamp bracket Z6010
51 Hinge base Z6011
52 Cover hinge Z6012
806 Microswitch Z6013
901 Phl. hd. screw Z6014
902 Key Z6015
903 Set screw Z6016
904 Ext. retaining ring Z6017
905 Nut M3 Z6018
906 Screw Z6019
907 Cap screw Z6020
908 Phl. hd. screw Z6021
909 Cap screw Z6022
910 Nut Z6023
911 Cap screw Z6024
912 Lock washer Z6025
913 Washer Z6026
914 Key Z6027
915 Cap screw Z6028
916 Lock washer Z6029
917 Washer Z6030
918 Key Z6031
919 Cap screw Z6032
920 Cap screw Z6033
921 Phl. hd. screw Z6034
922 Nut Z6035
Model PM-728V-T HEADSTOCK & SPINDLE Fig 2