Precision matthews PM-1236T User manual

1 Copyright © 2021 Quality Machine Tools, LLCPM-1340GT v8 2021-04
PM-1236T/1340GT Lathes
Model PM-1340GT Shown Above
Model PM-1236T and PM-1340GT Lathes
This manual was written for the PM-1340GT. The PM-1236T lathe,
also manufactured in Taiwan, is identical in all respects other than
overall weight, motor, bed length, and spindle height over the bed.
Items specic to the PM-1236T are noted in this color, italic.

2 Copyright © 2021 Quality Machine Tools, LLCPM-1340GT v8 2021-04
PM-1340GT
This manual contains essential safety advice on the proper setup, operation, maintenance, and service of
the PM-1340GT lathe. 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 lathe. As the owner of the lathe 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-1340GT machines as shipped from May 2016. There may be detail
di󰀨erences 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 addresses). Your feedback is
welcomed!
FAQ
POWER light o󰀨 (left)?
240 Vac power connected?
Overload circuit breaker tripped?
E-STOP button (right) pushed in?
(will pop out when rotated)
5A (low-voltage) fuse blown?
My lathe doesn’t
run at all
By design it should NOT run if
the Motor Control switch was
UP or DOWN when power is
connected.
Electrical schematic, Section 5:
move the Motor Control switch
to neutral, mid travel, to energize
the 24Vdc relay, thus restoring
normal conditions.
The motor didn’t run when
power was connected
Copyright © 2021 Quality Machine Tools, LLC
This material was originated by Precision Matthews. No portion of
the manual may be reproduced or distributed in any form without
the written approval of Quality Machine Tools, LLC.

3 Copyright © 2021 Quality Machine Tools, LLCPM-1340GT v8 2021-04
Section 1 INSTALLATION
THESE ARE THE MAIN POINTS TO WATCH OUT FOR!
But read the following pages for more information
• Handling the lathe is at least a two-man job.
• Lifting gear – sling, hoist or forklift – must be rated for at least 1 ton.
• Working location of the mill must allow space for removal of the belt cover at left, also
access to the coolant system (if installed) and the electrical box at the back of the head-
stock.
• Power requirement is 220 - 240V, 60Hz, 1φ (spindle motor 12A full load), or 3φ (9A full
load). Single phase only, 10A full load
• Extension cord not recommended; if no alternative, use 12 AWG not longer than 20 ft.
• Before connecting power check the following:
1. Machine on a rm footing, adequately secured to its stand.
2. Chuck camlocks tight, no wrench left in chuck.
3. Motor control switch OFF, mid-travel (Figure 1-6).
4. Carriage and cross slide approx. mid-travel, power feed disengaged (Figure 1-7).
5. Headstock gear selectors set for the lowest spindle speed (Figure 1-5).
1. Prepare the working location for the stand. If you in-
tend to use an engine hoist, there must be room for
the hoist, Figure 1-3. If not, a forklift and slings may
be a better option. If only an engine hoist is avail-
able, with limited space either side, the machine can
be fully assembled on a pair of 4-wheel dollies, then
rolled to its nal position. The assembly can then
be raised by screw jacks or other means to free the
dollies.
2. Position the LH and RH stand cabinets 40-1/4 inch-
es apart in the lathe’s nal location. Install the front
panel between the two stand cabinets.
3. Highly recommended!
Install leveling mounts rated for 250 lb each at the
corners of the stand cabinets. Depending on stud
size drill four 3/8" or 1/2" holes on the underside of
each stand. Alternatively, plan on leveling the ma-
chine with the supplied screws front and back, Fig-
ure 1-1, then pack metal shims under the cabinet
rims for a rock-solid installation.
4. Position the chip tray on the stands, aligning the
SETTING UP THE LATHE
The PM-1340GT is shipped in three packing cases, one
for the machine/chip tray/front panel/back splash, one
each for the left and right hand stand cabinets. The fol-
lowing procedure makes use of an engine hoist, mini-
mum weight rating 1 ton.
Figure 1-1 Supplied leveling screws
6 holes for mounting bolts with the corresponding
threaded holes on top of the cabinets. Optional:
apply double-sided adhesive tape to the bearing
surfaces on top of the cabinets. This will keep the
through holes aligned, making installation much
easier. For a solid installation — no rocking — use
very thin non-foam tape.
5. Remove the packing case from the pallet, then un-
bolt the machine from the pallet.
6. Balancing the lathe on a single-point hoist may take
a few tries. Run the carriage and tailstock down to
the headstock as far as possible without interfering
with the slings and stretchers, see the next step.
6. Run two 1000 lb slings under the lathe bed and up
to the hoist hook, with stretchers above and below

4 Copyright © 2021 Quality Machine Tools, LLCPM-1340GT v8 2021-04
Figure 1-2 Installation using an engine hoist
the bed to keep the slings outboard of the lead-
screw, feed shaft and motor control rod to avoid
damage to those components, Figure 1-2. Use 3/4"
plywood, 10" long for the stretcher under the bed
(thicker material will prevent the lathe from seating
properly on the chip tray). The upper stretchers can
be 10" lengths of 2x4 or other rigid material. For
easier alignment on the chip tray, tap wooden dow-
els into the holes at the tail stock end of the lathe
bed (not shown in Figure 1-2).
7. Slowly lift the lathe, controlling any tendency for it to
swing as it clears the pallet.
8. Roll the lathe into position, then hover it an inch or
so over the chip tray. This will allow you to mark the
perimeters of the lathe bed pedestals for the pur-
pose of caulking (optional — applies only if continu-
ous coolant ow is anticipated).
9. (Optional) Apply a thick bead of silicone caulk just
inside the marked perimeters on the tray.
10. Lower the lathe onto the chip tray, making sure that
LEVELING
Make sure the lathe is in its permanent location. The
leveling procedure ensures that the lathe bed is in the
same state as it was when the lathe was checked for ac-
curacy in manufacture — level from end to end along the
bed, and from front to back. In other words, no warping.
Make sure all leveling mounts under the cabinets are
properly weight bearing, rmly in contact with the oor.
Check and adjust level from end to end using a “preci-
sion machinist’s level”, if available. If not, use the most
reliable level on hand. Check and adjust level front-to-
back across the bed using a matched pair of spacer
blocks to clear the Vee tenons on the bed ways. The
blocks need to be ground, or otherwise accurately di-
mensioned. Alternatively, check for level on the ground
surface of the cross slide as the carriage is traversed
from end to end.
CONNECTING POWER
As shipped. the PM-1340GT is set for 220 V. If your
supply is nominally 240 V, it may be desirable to alter
CLEANUP
Metal surfaces may be protected by thick grease and/
or paper. Carefully remove these using a plastic paint
scraper, disposable rags and a light oil such as WD-40.
its six mounting holes are properly aligned. Excess
caulk squeezed out by the pedestals will form a
coolant-proof seal.
11. Install the six supplied M12 x 40 hex head bolts
with washers. Fully tighten the bolts. Re-check the
caulking on both pedestals.
12. Install the backsplash on the lathe.
Figure 1-3 Installation using a forklift

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Figure 1-4 Electrical box inputs/outputs
This conguration may vary depending on installed options, etc.
Figure 1-5 Motor control switches
connections to the 24V transformer in the electrical box.
If the lathe did not come with a pre-installed power cord,
connect to the power source using 12 AWG (minimum)
3-wire cord through a strain relief bushing sized for the
electrical box ports. Depending on installed options and
other factors, the entry point shown in Figure 1-4 may
not be available.
Spindle rotation
The motor control switches, Figure 1-5, are usually wired
so that the spindle turns counter-clockwise (viewed at
the chuck) when the motor control lever is down, see
Figure 1-7.
Some users prefer the lathe to run clockwise when the
control lever is down, in which case it may be necessary
to swap the wires to the motor control switches, Figure
1-5.
Alternatively, on a 3-phase installation, swap two of the
phases R, S or T on the terminal block. This will not af-
fect the coolant pump motor (if tted), which is single
phase.

6 Copyright © 2021 Quality Machine Tools, LLCPM-1340GT v8 2021-04
8. Check that there are no clamps or locks on moving
parts.
9. Set the carriage and cross slide to approximate
mid-travel.
10. Make certain that the motor control switch is set to
OFF, mid-travel, Figure 1-6.
11. Make certain that the power feed lever and lead-
screw split-nut lever are disengaged, Figure 1-7.
When both are disengaged, the cross slide and
carriage handwheels should turn freely.
11. Connect power. The power lamp (far left of the
orange color E-Stop button) should light, unless the
E-Stop button has been pushed in (it should pop
out when twisted clockwise).
12. Shift the motor control lever DOWN. The spindle
should turn forward, counter clockwise, viewed at
the chuck (nose) end.
INITIAL CHECKS
Read Section 3 if unsure about any item in the
following.
Do not connect power at this stage
1. Check oil level (sight glasses) in the headstock
and the apron. See Section 4, Figure 4-2.
2. Inject a small amount of oil into the gearbox oil
gallery, making certain that all seep holes in the
gallery are covered, Figure 4-3.
3. Lubricate the leadscrew and feed shaft oilers at the
tailstock end.
4. Remove the belt cover left of the headstock. Make
sure the belt is properly tensioned and set for the
low speed range. If not, re-position the belt, Figure
3-3.
5. Replace the belt cover.
6. If a chuck or faceplate is installed check tightness
of the three Camlocks on the spindle nose, Figure
3-27.
7. Set the spindle speed gear levers to L-2, Figures
1-5 and 3-4. With the drive belt set for low speed
this will give a speed of 90 rpm. Do not change
spindle speed, feed speed or feed direction
when the motor is running.
Figure 1-6 Headstock controls
Figure 1-7 Forward/Reverse motor control
Mid-travel OFF, Down FORWARD, Up REVERSE
Figure 1-8 Feed control levers

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13. Check the emergency function by pressing the
E-Stop button. The motor should stop. If this
doesn’t happen, the E-stop function is defec-
tive, and needs attention.
14. Reset (twist) the E-Stop button to restore power.
15. Return the motor control lever to OFF, mid-travel.
The motor should stop.
16. Shift the motor control lever UP. The spindle should
reverse, clockwise rotation, viewed at the chuck
(nose) end.
OPTIONAL TEST RUN PROCEDURE
Run the spindle for a few minutes, forward and reverse,
at each of the 6 speeds available with the low speed Vee
belt conguration, then repeat with the Vee belt changed
to high speed.
Note: In initial tests the carriage and cross slide should
rst be exercised manually, then under power.
After the initial test run, with 10 additional hours of ma-
chine time, the headstock should be drained and relled.
ALIGNING THE LATHE
The most important attribute of a properly set up lathe
is its ability to “machine parallel”, to cut a cylinder of uni-
form diameter over its entire length. In other words, no
taper.
Leveling of the lathe is a part of this, see earlier in
this section. Equally important is the alignment of the
center-to-center axis with the lathe bed, as seen from
above. [Vertical alignment is nowhere near as critical,
rarely a cause of taper unless the lathe is damaged or
badly worn.] For more information see the nal pages of
Section 4, Servicing the Lathe.

8 Copyright © 2021 Quality Machine Tools, LLCPM-1340GT v8 2021-04
Section 2 FEATURES & SPECIFICATIONS
MODEL PM-1340GT LATHE (PM-1236T)
General information
The PM-1340GT is a high quality gap-bed lathe designed for day-in, day-out use in the model shop or tool room.
Distance between centers is 40 in., swing over the bed 13 in. (19-1/8 in. with the gap insert removed). With an all-up
weight of over 1300 lb, choice of precision chucks, plus a range of speeds from 90 to 1800 rpm, the PM-1340GT
is one of the most versatile small machines available. The spindle nose is D1-4 Camlock. A quick-change carriage
feed gearbox provides a full range of leadscrew ratios for U.S. (TPI) screw cutting, without external gear swapping,
together with an independent power feed for both saddle and cross slide. The power feed shaft is driven through a
friction clutch that allows the saddle to be stopped with micrometer precision at any point along the bed. A coolant
system and taper turning attachment are two of the many options available for the PM-1340GT.
The spindle has a 1-9/16 in. clearance bore and MT5 internal taper. It runs in tapered-roller bearings, and is driven
by a 9-speed gearbox, coupled by Vee-belt to a 2 HP (1500 W) 220-240 Vac three-phase motor (single-phase op-
tional). Two-step Vee pulleys provide a choice of high and low speed ranges, giving a total of 12 spindle speeds — 6
high range plus 6 low range.
PM-1340GT (PM-1236T) Floor plan: dimensions approximate (not to scale)
65-1/2"

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Dimensions, approximate overall Including stand: Width 69-1/4 in. (65-1/2 in.), Height 48-1/2 in.
Depth 22 in. at chip tray, add 5 in. for cross slide
Weight (lathe, excluding stand), net 1100 lb (850 lb)
Welded steel stand, net 250 lb
Cast iron stand, net 500 lb
Power requirement (two options) 1. 220 - 240Vac, 60 Hz, 1Ø, 12A full load
2. 220 - 240Vac, 60 Hz, 3Ø, 9A full load
Motor type TEFC, 1.5 kW (2 HP), 1725 rpm
1.5 HP, 1Ø only, 10A full load
Work envelope
Gap insert length 7-1/2 in.
Distance between centers 40 in. 36 in.
Swing over gap 19-1/8 in. 18 in. diameter
Swing over bed 13 in. 12 in. diameter
Swing over cross slide 6-1/2 in. 6 in. diameter
Cross-slide travel 6-3/4 in.
Compound (top slide) travel 3-1/2 in.
Center rest (steady rest) capacity 2-1/2 in. diameter
Follower rest capacity 1-1/2 in. diameter
Drive system
High/Low belt drive with 6-speed gearbox
Low range, rpm 90, 135, 205, 205, 308, 475
High range, rpm 335, 505, 770, 780, 1160, 1800
Carriage drive, thread cutting Leadscrew 8 tpi
Inch threads Choice of 40, from 4 to 112 TPI
Metric threads Choice of 24, from 0.25 to 7.5 mm pitch
Carriage drive, turning operations Choice of feed rates from 0.0027 to 0.08 in./spindle rev
Cross slide drive Choice of feed rates from 0.0015 to 0.04 in./spindle rev
Spindle
Chuck/faceplate attachment D1-4 Camlock
Internal taper MT5
Spindle bore 1-9/16 in.
Spindle length, chuck removed 13-3/4” (add approx 3-1/2 in. for 3-jaw chuck)
Tailstock
Internal taper MT3
Quill travel 4 in.
PM-1340GT (PM-1236T) SPECIFICATIONS

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Everyday precautions
• This machine is intended for use by experienced users familiar with met-
al-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 parti-
cles).
• Wear proper apparel and non-slip footwear – be sure to prevent hair, cloth-
ing or jewelry from becoming entangled in moving parts. Gloves – including
tight-tting 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, toolholder(s) and machine ways are secure before
commencing operations.
• 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 220 Vac 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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Section 3 USING THE LATHE
MOTOR CONTROL
Before doing anything, check the installation in-
structions and power-up procedure in Section 1
Before connecting power to the lathe, be sure the mo-
tor control lever on the carriage apron is set to OFF,
mid-travel. Connect the lathe to a 220-240 Vac outlet. In
SPINDLE DRIVE TRAIN
Double-groove pulleys connect the motor to the head-
stock gearbox, Figure 3-3. The low speed conguration
Figure 3-3 Vee belts drive the headstock gearbox
WHAT IS NOT IN THIS SECTION ...
The PM-1340GT is a conventional engine lathe that re-
quires little explanation except for details specic to this
particular model — speed selection, thread cutting, and
the carriage/cross slide power feed system. Because
the user is assumed to be familiar with general purpose
metal lathes, this section contains very little tutorial.
CONTROL PANEL
In addition to three gear shift levers (speed and feed
direction) the control panel also includes a “jog” control.
This a momentary type push-button independent of the
motor control switch on the carriage apron. When op-
erated, the jog button runs the spindle in the forward
direction, stopping when released.
Figure 3-1 Control panel
normal conditions the POWER lamp should light provid-
ed the E-STOP button has not been activated (pushed
in). Operate the motor control lever to run the spindle
forward (lever DOWN), then STOP (mid-travel), and re-
verse (lever UP).
Figure 3-2 Motor control lever
This photo shows the motor switch DOWN, forward spindle
rotation. Set the switch to OFF, mid-travel, before connecting
power.

12 Copyright © 2021 Quality Machine Tools, LLCPM-1340GT v8 2021-04
gives spindle speeds from 90 to 475, high speed from
335 to 1800 rpm. Because many users nd that one
range or the other is suitable for most of their work, there
is typically little need to swap belts. If the drive needs
to be recongured, loosen the lever securing the motor
platform to the slotted stay, Figure 3-3. Raise the motor
to de-tension, reposition the Vee belt, then lower the mo-
tor to re-tension — not fully weight bearing, just enough
to drive reliably without slipping. Re-tighten the lever.
SPINDLE SPEEDS
The PM-1340GT has a six-speed headstock gearbox
with two shift levers L-H and 1-2-3, Figures 3-1 and
3-4. Before changing speed, STOP THE MOTOR,
Figure 3-2, then move each shift lever to the desired
setting. This calls for care and patience because it
is not always possible to go directly from one mesh
to another. Move the spindle back and forth by hand
while easing the lever into its detent (meshed) position.
Don’t use the JOG button in this process — this
may cause gear damage.
CARRIAGE FEED DIRECTION
The black knob below the speed selection levers on the
front panel, Figure 3-1, determines whether the power
feed is right to left — the usual direction for turning and
thread cutting — or reversed. The selected direction ap-
plies to both the leadscrew and the carriage/cross slide
power feed.
Before changing feed direction, STOP THE MOTOR.
Hand-turn (jiggle) the spindle while feeling for the mesh,
as above.
CARRIAGE FEED GEARBOX
The carriage feed gearbox (a.k.a. quick-change gear-
box) has two separate outputs: 1. An 8 TPI leadscrew,
used primarily for thread cutting, linked to the carriage
by a split nut in the apron, and; 2. A keyed power-feed
shaft driving a worm, in the apron, which in turn drives
either the carriage or the cross slide.
SPINDLE SPEED (RPM)
1 2 3
H1800 770 1160
L475 205 308
H780 335 505
L205 90 135
Headstock Vee
belt pulley
Figure 3-4 Vee belt congurations
High
range
Low
range
For all TPI standard
threads (U.S.A.) the
127T gear is simply
an idler between up-
per and lower gears.
Figure 3-6
Standard TPI setup
Figure 3-5 External change gears
The carriage feed gearbox is driven by external change
gears, Figure 3-5.
For all standard U.S. thread cutting (TPI) the exter-
nal gears are always 40T upper, 40T lower — see Fig-
ure 3-6. For these non-metric operations the power-feed
rate relative to spindle speed is entirely controlled by the
two gear shift levers below the main control panel, Fig-
ure 3-1. Note also that the 40T-40T setup delivers the
feed rates shown in the thread chart, Figure 3-7.
The knob with pointer, right of the thread chart, selects
the gearbox output — carriage feed shaft (left, counter

13 Copyright © 2021 Quality Machine Tools, LLCPM-1340GT v8 2021-04
clockwise), or leadscrew (right, clockwise). STOP THE
MOTOR! Hand-turn (jiggle) the spindle while feeling for
the mesh, as above.
SETUP FOR METRIC THREAD CUTTING
The large gears in Figure 3-5 are transposing gears,
120T and 127T. They allow a standard-thread leadscrew,
in this case 8 TPI, to cut metric threads. The transposing
gears are keyed together.
For U.S. thread cutting, the 127T larger gear is simply
an idler, transferring the drive from the upper gear to
the lower gear. In this conguration, the spacer bushing
is outside the lower gear.
For metric thread cutting, the lower gear is driven by the
120T transposing gear. In this conguration the spacer
bushing is inside the lower gear. See the thread cutting
tables, Figure 3-18.
Any change to the drive train typically calls for one or
both of the upper and lower gears to be changed. This
will require the transposing gear pair to be repositioned.
The procedure for this is:
• Remove the M6 socket head screws from the upper
and lower gear shafts.
• Remove the gears, washers, keys and bushing (lower
gear only).
• While holding the gear support casting (quadrant)
with one hand, use a 15 mm wrench to loosen the
M10 hex nut hidden under the 127T gear. Allow the
casting to swing downward.
Figure 3-7 Thread chart
Characters A through E and 1 through 8 along the bottom of
the chart refer to detent holes for the gear levers. (The chart is
oset to the left, so the characters may not be directly in line
with the holes.) Note that the power feed rates in the chart,
inches/spindle revolution, apply only to the 40T-40T external
gear setup. The feed rates given are for carriage motion ("Lon-
gi Direction", Figure 3-11). Cross slide motion ("Cross Direc-
tion") is one half the stated value. Metric setups can be used
for power feeding, but the rates will not be as shown. See also
the thread cutting tables, Figure 3-15, etc.
• Loosen the M10 hex nut securing the transposing
gears to the support casting.
• Install the upper and lower gears.
• Bring the transposing gears into mesh with the lower
gear, trapping a scrap of bond paper (letter stock) be-
tween the two to hold them at the correct separation.
• Tighten the transposing gears in position, then re-
move the paper. Check for working clearance be-
tween the gears.
• Swing the gear support casting upward to mesh the
127T gear with the upper gear, again using a paper
scrap for separation.
• Tighten the gear support casting.
CROSS SLIDE AND COMPOUND
The cross slide and compound, Figure 3-8, both have
10 TPI leadscrews, with 100-division graduated collars,
so each division represents a “real” motion of 0.001”. On
the cross slide dial, only, this shows as ϕ 0.002”, mean-
ing that a 0.001” depth of cut reduces the diameter of
the workpiece by 0.002”. The second row of divisions on
each collar reads in millimeters, 0.02 mm/division on the
compound, 0.04 mm/division on the cross slide. [These
collars have 127 divisions, so the reading is “true met-
ric”.]
Figure 3-8 Cross slide and compound dials
LOCKING THE SLIDES
When face-cutting large diameter surfaces, for example,
it is often desirable to lock the carriage. Less frequently
it can be helpful to lock, or at least sti󰀨en, the sliding
motion of the cross slide or compound, Figures 3-9 and
3-10.

14 Copyright © 2021 Quality Machine Tools, LLCPM-1340GT v8 2021-04
FEEDSHAFT CLUTCH
The clutch shown in Figure 3-12 disengages the pow-
er feed if the carriage or cross slide hits an obstruction
when power feeding, thus minimizing the potential for
damage. This could be the result of either an accidental
event, or deliberately stopping the carriage at a precise
location set by a micrometer stop xture, if installed, Fig-
ure 3-13.
The clutch comprises a pair of spring loaded steel balls
bearing on a detent disc driven by the carriage feed gear-
box. Spring pressure is adjusted by two set screws on
either side of the feed shaft, arrowed (1) in Figure 3-12.
Setting the spring pressure is a process of aiming for the
best compromise between too high — damaging feed
pressure — and too low, which might mean unexpected
stopping for no good reason. Setting the clutch to work
reliably with a micrometer carriage stop is a good exam-
ple of such a compromise: start with low spring force,
then work up in small increments until the carriage stops
in the same location (say ± 0.002”, assuming a constant
depth of cut and feed rate).
ENGAGING THE POWER FEED
Power feed controls are located on the apron, Figure
3-11. The split-nut lever engages the leadscrew, typ-
ically used only for thread cutting (rotary knob on the
gearbox clockwise), described later.
The power feed lever is active only when the keyed
feed shaft is rotating (rotary knob on the gear box coun-
terclockwise). In its neutral (detent) position the lever
pinion is captive, a safety measure to avoid accidental
engagement of the power feed unless the lever is rst
shifted to the left or right.
Figure 3-11 Power feed levers on the apron
Carriage feed ("Longi") — lever right & up
Cross slide feed — lever left & down
To engage either power feed move the power feed lever
gently, feeling for the gears to mesh as you go. If the
gears don’t engage at the rst try, use the appropriate
handwheel to jiggle the carriage or cross slide, whichev-
er one you wish to move under power.
Figure 3-9 Carriage and cross slide lock screws
Figure 3-10 Compound lock screw

15 Copyright © 2021 Quality Machine Tools, LLCPM-1340GT v8 2021-04
Figure 3-13 Micrometer carriage stop
Figure 3-12 Feedshaft clutch
Pressure adjusting screws are arrowed (1). Arrow (2) is the
leadscrew shear pin, brass or similar soft material.
COMPOUND SETUP FOR THREAD CUTTING
Thread cutting on the lathe is unlike most other turning
operations, for two reasons: 1. The cutting tool must be
precisely ground with an included angle of 60 degrees
for most American and Metric threads, and; 2. It is pref-
erable to feed the tool into the workpiece at an angle
so it cuts mostly on the left ank of the thread. The cor-
rect angle relative to the cross slide (zero degrees) is a
subject of debate — should it be 29, 29-1/2 or 30 de-
grees? Many machinists use 30 degrees, others prefer
29 degrees, because it holds the cutting tool marginally
clear of the right ank of the thread — close enough for
cleanup of the ank, while at the same time avoiding
appreciable rubbing.
Figure 3-14 Compound set for 30oinfeed
For 29 degrees estimate an additional 1 degree clockwise be-
yond the engraved scale.

16 Copyright © 2021 Quality Machine Tools, LLCPM-1340GT v8 2021-04
CUTTING TPI THREADS
This procedure assumes that a single point thread cut-
ting tool will be used, and that the threading dial assem-
bly has been pivoted forward to engage worm gear with
leadscrew, Figure 3-11. Note that the threading dial is
not used for metric threads.
For metric and UNC/UNF threads the tool is ground to
a precise included angle of 60o. It is installed so that its
anks are exactly 30o either side of the cross axis, ideal-
ly with the compound o󰀨set as Figure 3-14. Single-point
threads are typically cut in 10 or more successive pass-
es, each shaving a little more material o󰀨 the workpiece.
To make the rst thread-cutting pass the leadscrew is run
at the selected setting, Figure 3-15, and the carriage is
moved by hand to set the cutting tool at the starting point
of the thread. With the tool just grazing the workpiece,
the split-nut lever is lowered to engage the leadscrew.
This can be done at any point, provided you intend to
leave the split-nut engaged throughout the entire multi-
pass process.
When the rst pass is completed, the tool is backed out
clear the workpiece (one turn of the cross slide hand-
wheel), and the spindle is reversed to bring the carriage
back to the starting point. The cross slide is returned
to its former setting, then the tool is advanced a few
thousandths by the compound for the next pass. Each
successive pass is done in the same way, each with a
slightly increased infeed setting of the compound.
Many users save time by disengaging the split-nut at the
end of each pass, reversing the carriage by hand, then
re-engaging, usually by reference to the threading dial,
Figure 3-16.
If the TPI number is an even multiple of 4 re-engage-
ment can be done at any point — forget the threading
dial.
For all other TPI numbers every engagement, includ-
ing the rst, must at the point where a specic line
on the threading dial comes into alignment with the da-
tum mark. If not, the second and subsequent passes will
be out of sync. In some cases, Figure 3-16, there is a
choice of lines for re-engagement, but in every case the
process calls for careful timing. [NOTE: Disengagement
and re-engagement of the split-nut is not applicable to
metric threads].
Typical depths of cut per pass vary from an initial 0.005”
or so, to as little as 0.001”, even less. A nishing pass
or two with increments of only 0.0005” (or none at all)
to deal with the spring-back e󰀨ect can make all the dif-
ference between a too-tight thread and one that runs
perfectly. Assuming that the compound is set over at 29
or 30 degrees, the total depth of cut is approximately
0.69 times the thread pitch, P (this equates to a straight-
in thread depth of 0.6 times P). There may be a need
for a few thousandths more in-feed than 0.69P, almost
certainly not less.
THREADS PER INCH
TPI 4 4-1/2 4-3/4 5 5-1/2 6 6-1/2 7
Gearbox A1 A2 A3 A4 A5 A6 A7 A8
TPI 8 9 9-1/2 10 11 12 13 14
Gearbox B1 B2 B3 B4 B5 B6 B7 B8
TPI 16 18 19 20 22 24 26 28
Gearbox C1 C2 C3 C4 C5 C6 C7 C8
TPI 32 36 38 40 44 48 52 56
Gearbox D1 D2 D3 D4 D5 D6 D7 D8
TPI 64 72 76 80 88 96 104 112
Gearbox E1 E2 E3 E4 E5 E6 E7 E8
Figure 3-15 Gearbox settings for TPI threads

17 Copyright © 2021 Quality Machine Tools, LLCPM-1340GT v8 2021-04
Figure 3-17 Threading dial visualization for selected U.S. threads
TPI Line TPI Line TPI Line TPI Line
4 / 9-1/2 1, 5 22 1 - 8 52 1 - 8
4-1/2 1, 5 10 1 - 8 24 1 - 8 56 1 - 8
4-3/4 1 11 1, 3, 5, 7 26 1 - 8 64 /
5 1, 3, 5, 7 12 1 - 8 28 1 - 8 72 1 - 8
5-1/2 1, 5 13 1, 3, 5, 7 32 / 76 1 - 8
6 1 - 8 14 1 - 8 36 1 - 8 80 1 - 8
6-1/2 1, 5 16 / 38 1 - 8 88 1 - 8
7 1, 3, 5, 7 18 1 - 8 40 1 - 8 96 1 - 8
8 / 19 1, 3, 5, 7 44 1 - 8 104 1 - 8
9 1, 3, 5, 7 20 1 - 8 48 1 - 8 112 1 - 8
Figure 3-16 Using the threading dial
The symbol “/” means “forget the dial” – re-engage wherever the split-nut
can be closed. For all other TPI values the split-nut is re-engaged only
when the datum coincides with a specic line – or lines – according to the
following rules. See Figure 3-17 for more options.
1. Divide the TPI value by 2: If this gives a whole number, example 6/2 =
3, re-engage at ANY line. In the table this shows as 1 – 8.
2. If the TPI value is a whole number not divisible by 2, example 7, re-
engage on the start line, or any line at right angles to it. In the table this
shows as 1, 3, 5, 7 (but could be 2, 4, 6, 8).
3. If the TPI value is fractional, but becomes a whole number when mul-
tiplied by 2, example 4-1/2, re-engage on the start line or its diametrical
opposite. In the table this shows as 1, 5 (but could be 2, 6 or 3, 7,
etc.).
4. If the TPI value is fractional, but becomes a whole number when mul-
tiplied by 4, example 4-3/4, re-engage only on the start line. In the table
this shows as 1(but could be any starting number).

18 Copyright © 2021 Quality Machine Tools, LLCPM-1340GT v8 2021-04
CUTTING METRIC THREADS
For metric thread cutting the split-nut on the apron must
be left engaged throughout the entire process. This
not the case for U.S. standard TPI threads, for which the
normal procedure is to disengage the half-nut after each
METRIC PITCH (mm)
mm 6 4.8 4
Gearbox A1 A4 A6
mm 3 2.4 2
Gearbox B1 B4 B6
mm 1.5 1.2 1
Gearbox C1 C4 C6
mm 0.75 0.6 0.5
Gearbox D1 D4 D6
mm 0.3 0.25
Gearbox E4 E6
METRIC PITCH (mm)
mm 7.5 6 5
Gearbox A1 A4 A6
mm 3.75 3 2.5
Gearbox B1 B4 B6
mm 1.5 1.25
Gearbox C4 C6
mm 0.75
Gearbox D4
METRIC PITCH (mm)
mm 4.5 4 3
Gearbox A1 A2 A6
mm 2.25 2 1.8 1.5
Gearbox B1 B2 B4 B6
mm 1 0.9 0.75
Gearbox C2 C4 C6
mm 0.5 0.45
Gearbox D2 D4
mm 0.25
Gearbox E2
Figure 3-18 Metric thread cutting tables
pass, reverse the carriage, then re-engage at a specif-
ic indication on the threading dial (see above). NOTE:
For metric threads the lower of the two external change
gears is driven by the inner (120T) transposing gear.

19 Copyright © 2021 Quality Machine Tools, LLCPM-1340GT v8 2021-04
TAILSTOCK
The tailstock leadscrew is 10 TPI, with a travel of 4 inch-
es. Like the compound, the tailstock has two graduat-
ed collars, one reading 0.001”/division, the other 0.02
mm/division. To remove tooling from the tailstock taper
(MT3) turn the handwheel counter-clockwise (handle
end view) until resistance is felt, then turn the handle a
little more to eject the tool. Conversely, to install a taper
tool make certain that the quill is out far enough to allow
rm seating.
Figure 3-19 Tang slot in tailstock quill
For taper turning the tailstock may be o󰀨set by adjusting
the set screws on either side, Figure 3-20. To move the
tailstock to the rear, for instance, the screw on the lever
side would be unscrewed, then the opposing set screw
would be screwed in to move the upper assembly.
Figure 3-20 O󰀨set adjustment
A visual indication of the o󰀨set is provided by the scale,
but this is not a reliable measure for precise work. In
practice, the only way to determine the o󰀨set precisely
is to "cut and try' on the workpiece, homing in on the
correct degree of o󰀨set in small increments.
The same issues arise when re-establishing "true zero"
of the tailstock, in other words returning it to the normal
axis for routine operations. One way to avoid cut-and-try
is to prepare in advance a bar of (say) 1" diameter qual-
ity ground stock, with precise center drillings at both
ends (do this by indicating for zero TIR in a 4-jaw chuck,
not in a 3-jaw unless known to be equally accurate). The
prepared bar can then be installed between centers and
indicated along its length.
STEADY & FOLLOWER RESTS
The hinge-type steady rest, Figure 3-21, can be mount-
ed anywhere along the lathe bed. It makes possible
cutting operations on long, slender workpieces between
centers, or held at one end by chuck. The steady rest
is often used in combination with the carriage-mounted
follower rest, Figure 3-22.
To set the ngers on the workpiece, rst swing open the
upper casting. Make certain that all three ngers are
freely adjustable by thumbwheel. If not, loosen and re-
lock the set screws. Raise the two lower ngers to just
touch the workpiece — not deecting it — then close
and secure the upper casting. Lower the top nger to
Figure 3-21 Steady rest

20 Copyright © 2021 Quality Machine Tools, LLCPM-1340GT v8 2021-04
just touch the workpiece, then apply oil at the point of
contact.
The follower rest is secured to the saddle with two
socket head screws. Adjust the follower ngers as
described for the steady rest.
Figure 3-22 Follower rest
GAP BED
A 7-1/2 inch long section of the bed at the headstock
end can be removed to allow turning of diameters up to
19-1/8 in., Figure 3-23.
Insert removal is not a routine procedure. Do it only
if there is a specic need.
To remove the gap insert back out the pusher screws
two or three turns, then remove the four M10 screws se-
curing the insert to the bed. To minimize cosmetic dam-
age, cut through the paint along the joint between insert
and bed using a sharp knife or pointed scraper.
Insert M6 screws into the two locating pins, then jack
them out using a slide hammer or other means. Tap the
insert free with a soft-face mallet.
Before re-installing the insert be certain that all mating
surfaces are scrupulously clean. Set the insert in place,
gently tap in the two locating pins, then install the four
large bolts (snug, but not fully tightened). Jack the insert
to the right with the pusher screws to close the gap, if
any, between the ground surfaces of the bed ways at the
join (a visible parting line is acceptable, but a disconti-
nuity that snags the carriage is not). If a satisfactory join
cannot be achieved, it may be necessary to remove and
re-install the insert from scratch.
Figure 3-23 Gap insert