LittleMachineShop.com HiTorque 5100 User manual

The premier source of tooling, parts, and accessories for bench top machinists.
HiTorque 7x16 Mini Lathe Users Guide
Model 5100 • Model 7350 Deluxe
from LittleMachineShop.com

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© Copyright 2019 LittleMachineShop.com
All rights reserved.
Photos © Copyright 2019 PhotoBoost.com
All rights reserved.
Written by Chris Wood of LittleMachineShop.com
Revision 2, August 2019
LittleMachineShop.com
https://www.littlemachineshop.com
396 W. Washington Blvd. #500, Pasadena, CA 91103
[phone] • Fax [phone]

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Contents
Introduction ................................................................................5
Specifications ..............................................................................5
Safety Considerations .....................................................................6
General Safety...........................................................................6
Lathe Safety .............................................................................6
Electrical Safety.........................................................................6
Machine Safety ..........................................................................7
Features.....................................................................................8
Front View ...............................................................................8
Rear View ................................................................................9
Accessories .................................................................................9
Cleaning ................................................................................... 10
Assembly .................................................................................. 10
Mounting Your Lathe .................................................................... 10
Operating Controls ...................................................................... 11
Motor Controls......................................................................... 11
Power Feed Forward/Neutral/Reverse Lever ..................................... 12
Power Feed Lever ..................................................................... 12
Carriage Hand Wheel ................................................................. 12
Cross Slide Feed Handle.............................................................. 13
Compound Rest Feed Handle ........................................................ 13
Digital Position Readout (Model 7350 only) ....................................... 13
Compound Rest Rotation............................................................. 14
Tailstock Locking Lever .............................................................. 15
Tailstock Quill Hand Wheel .......................................................... 15
Tailstock Quill Digital Position Readout (Model 7350 only) ..................... 15
Tailstock Quill Locking Lever........................................................ 15
Adjustments .............................................................................. 15
Carriage ................................................................................ 16
Cross Slide Gibs........................................................................ 16
Cross Slide Nut ........................................................................ 17
Compound Rest Gibs.................................................................. 18
Apron Position ......................................................................... 18
Tailstock Position ..................................................................... 18
Half Nuts ............................................................................... 19
Lead Screw Mounting ................................................................. 20
Drive Belt............................................................................... 20

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Maintenance .............................................................................. 21
Cleaning ................................................................................ 21
Lubrication ............................................................................. 21
Changing Chuck Jaws.................................................................... 23
Mounting Work in a 3-Jaw Chuck ...................................................... 24
Grinding Tool Bits........................................................................ 24
How to Grind Tool Bits ............................................................... 26
Grind the Front Relief ................................................................ 26
Grind the Left Side Relief............................................................ 26
Grind the Top Rake ................................................................... 26
Round the Nose........................................................................ 26
Adjusting Tool Bit Height ............................................................... 27
Turning .................................................................................... 27
Manual Turning ........................................................................ 27
Turning with Power Feed ............................................................ 28
Facing ..................................................................................... 29
Turning Angles ........................................................................... 30
Cutting Threads .......................................................................... 30
Change Gears .......................................................................... 31
Threading Dial ......................................................................... 34
Tool Bit ................................................................................. 35
Compound Angle ...................................................................... 36
Setting the Cutting Tool ............................................................. 36
Threading Process..................................................................... 37
Common Accessories .................................................................... 38
Cut-Off Tool Holder................................................................... 38
Quick Change Tool Post .............................................................. 38
Indexable Turning Tools.............................................................. 39
4-Jaw Chuck ........................................................................... 39
Faceplate............................................................................... 40
Centers and Dogs...................................................................... 40
Steady Rest and Follower Rest ...................................................... 41
Parts Diagram ............................................................................ 42
Parts List .................................................................................. 43
DRO Parts............................................................................... 46
Wiring Diagram........................................................................... 47

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Introduction
This user’s guide covers care and operation of the LittleMachineShop.com
HiTorque 7x16 Mini Lathe. Be sure to read and understand the safety guidelines
presented in this book before using your HiTorque Mini Lathe.
The HiTorque 7x16 Mini Lathe is available in two models:
•Model 5100 is the standard version.
•Model 7350 is the deluxe version. It includes all the features of Model
5100 and adds:
oDigital position readouts (DRO) on compound rest, cross slide, and
tailstock
oMetal hand wheels and chrome levers
oQuick change tool post (QCTP) set with five tool holders
Chris’ Tip: You can upgrade your Model 5100 lathe with the following kits
available from LittleMachineShop.com:
•Part number 5675: Digital Position Readout, 2-Axis Mini Lathe
•Part number 5879: Digital Position Readout, Mini Lathe Tailstock
•Part number 3937: Knob and Hand Wheel Kit
•Part number 3112: Quick Change Tool Post Set, 0XA, Mini Lathe
Installation of all four kits creates a machine that is functionally identical to a
Model 7350 deluxe lathe.
Specifications
Swing over bed
7.1" (180 mm)
Swing over saddle
4.3" (110 mm)
Between centers
16.1" (410 mm)
Spindle taper
Morse taper 3
Tailstock taper
Morse taper 2
Spindle bore
0.8" (20 mm)
Cross slide travel
2.6" (65 mm)
Compound rest travel
2.2" (55 mm)
Spindle speed
50–2500 RPM
Automatic feed rate
0.004" (0.1 mm)/ revolution
Range of threads
4-80 TPI (0.3-8 mm)
Power requirements
120 V 60 Hz 8 Amps
Spindle motor output
0.67 hp (500 Watts)

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Safety Considerations
Always use common sense when using a power tool. Besides the general safety
rules for any power tool, following also are specific considerations for the mini
lathe.
General Safety
•Use common sense. Think through the results of your actions before you
act.
•Understand the operation of the machine. Do not operate the machine if
you do not know what is going to happen.
•Learn, don’t experiment. Study, understand, and do things where you have
a clear expectation of the outcome. Don’t “see what will happen.”
•You are responsible for your own actions. We can’t be held responsible for
your actions when you use the machine.
Lathe Safety
•Your mini lathe is just that, a mini, or small lathe. Don’t attempt jobs that
are beyond its capacity.
•Check the workpiece after you place it in the chuck or other work holding
device. Be sure it is secure before turning on the lathe.
•Don’t wear loose clothing or jewelry when operating the lathe.
•Stop the spindle and make sure the machine is in a safe condition before:
oOpening or removing safety shields
oReaching into work area
oChanging or adjusting tools
oChanging or adjusting workpieces
oChanging speed ranges
oClearing chips or coolant
•Inspect cutting tools for sharpness, chips, and cracks before each use.
Replace dull, chipped, or cracked cutting tools immediately.
•Handle cutting tools with care. Cutting edges are very sharp and can cause
lacerations.
•Do not use unbalanced workpieces or fixtures in the spindle
•Remove all tools (wrenches, chuck keys, locking pins, and so on) from the
spindle immediately after using them.
Electrical Safety
•Plug the machine into a grounded receptacle. Note that the machine does
not work properly on a ground fault circuit interrupter (GFCI) receptacle.

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•Ensure that all components are properly grounded. The easiest way to
ensure this is to plug your machines and devices into grounded outlets that
you have tested.
•Use caution when using liquids and electricity. Ensure that coolants and
lubricants are kept away from high voltage electrical components.
•Disconnect all components from the power receptacle before servicing.
•In the event of a power outage, turn off all components to ensure that the
machine does not restart unexpectedly.
Machine Safety
•Keep bystanders, children, and visitors a safe distance away while operating
any power tool.
•Read the manual. Know the operation of every control before you attempt
any operation of the machine.
•Make sure that all guards are in place and functioning before operating the
machine.
•Check for damage and abnormal wear before operating the machine.
•Always wear safety glasses (side shields are recommended) that are ANSI
Z87.1-2003 compliant.
•Wear hearing protection (ear plugs or ear muffs) when operating loud
machines.
•Wear appropriate clothing; no rings, gloves, neckties, jewelry, or loose-
fitting garments. Bind long hair or wear a hat.
•Do not use compressed air for cleaning machines. A shop vacuum works well
and is much safer.
•Don’t operate machinery while under the influence of drugs or alcohol.
•Ensure that your machines are well lit. Ensure that your shop is well lit, and
have additional task lighting where appropriate.
•Maintain a clean and uncluttered work area.
•Avoid pinch points.
•Never leave a running machine unattended.
•Do not force or overload machinery.
•Use appropriate cutting tools with appropriate feeds and speed.
•Cutting tools get hot during use and can cause burns if handled
inappropriately.
•Do not attempt to use workpieces that are too large or two heavy for the
machine.
•Maintain your machines. Ensure that it is well-adjusted and in a safe state.
•Clear chips with a brush or other tool, never with your hands or with
compressed air.

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•Make sure the machine is on a flat, level surface that is capable of
supporting the weight of the machine plus fixtures, vise, and workpiece.
•Clamp work securely. Cutting forces are significant and can turn workpieces
that are not secured into projectiles.
•Be aware that chips and dust from some materials (magnesium, for
example) are flammable. Understand the materials you are using.
Features
Front View
1. Motor controls
2. Headstock
3. 3-jaw chuck
4. Carriage
5. Cross slide
6. Tool post
7. Compound rest
8. Compound rest feed handle
9. Tailstock quill
10.Tailstock quill locking lever
11.Tailstock locking lever
12.Tailstock quill hand wheel
13.Change gear cover
14.Carriage hand wheel
15.Apron
16.Cross slide feed handle
17.Power feed lever
18.Threading dial
19.Bed ways
20.Lead screw
15
13
1
3
7
16
17
6
8
19
20
11
14
12
10
9
5
4
2
18

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Rear View
Accessories
The following accessories come with the HiTorque Mini Lathe.
•Chuck key for the 3-jaw chuck
•Outside jaws for the 3-jaw chuck
•Change gears: 21, 30, 35, 40 (2),
45, 50, 55, 57, 60, and 65 teeth
•Hex wrenches: 3, 4, 5, and 6 mm
•Open end wrenches: 8 x 10 mm
and 14 x 17 mm
•#2 Morse taper dead center
•Oil can (plastic)
Power feed forward/
neutral/reverse lever

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Cleaning
Your lathe will arrive coated with heavy oil to protect it from corrosion during
shipment. Wipe off any excess with rags or paper towels, but leave a light
coating in place.
See “Lubrication”on page 21 for specific recommendations for lubricants.
Assembly
There are two things to do to assemble your lathe.
1. Reverse the chrome crank handle on the cross slide.
2. Install the mounting feet and spreader bars on the lathe. Use the M6 socket
head cap screws that are furnished. Instead of installing the mounting feet,
you may wish to mount your lathe to a bench as described in the next
section.
Mounting Your Lathe
The HiTorque Mini Lathe comes with rubber feet and spreader bars that attach
to the same holes used to secure the lathe for shipping. If you want your lathe
to be portable, simply install these spreader bars and feet.
You can also bolt your lathe to your workbench. The following diagram shows
the holes required.
Mount the lathe to the workbench with M6 bolts. The bolts should be about 0.4"
(10 mm) longer than the thickness of the workbench. Use fender washers on

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the underside of wooden benches to prevent the bolt heads from pulling
through.
Operating Controls
There are several controls used to operate the lathe. Become familiar with
them before you use the lathe.
Motor Controls
1. Power and emergency stop (E-stop) switch
2. Forward/off/reverse switch
3. Speed control
The red E-stop switch latches in the off position when you press the red button.
To turn the switch on, press the green button.
The power switch interrupts the input power to the speed control circuit
board.
The forward/off/reverse switch switches the polarity of the speed control
circuit board output power between the speed control circuit board and the
motor.
You control the motor speed by adjusting a potentiometer that provides the
speed setting value to the speed control circuit board.
You can change the motor direction at any time and at any speed that safety
allows. The motor will make a controlled stop or a controlled change of
direction.
1
2
3

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To power up the lathe:
1. Turn the speed control to the minimum speed position.
2. Place the forward/off/reverse switch in the off position.
3. Turn on the power switch by pressing the green button.
To start the lathe:
1. Ensure that the speed control is set to the minimum speed position.
2. Move the forward/off/reverse switch to the appropriate position.
3. Advance the speed control to the desired speed.
To stop the lathe:
1. Turn the speed control to the minimum speed position.
2. Move the forward/off/reverse switch to the off position.
3. If you want to power down the lathe, press the red switch to turn off the
power.
Power Feed Forward/Neutral/Reverse Lever
The power feed forward/neutral/reverse lever controls the direction of
rotation of the lead screw. When this lever is in the forward, or top, position
the lead screw moves the carriage toward the headstock. When this lever is in
the reverse, or bottom, position, the lead screw moves the carriage away from
the headstock. In the center, or neutral, position the lead screw is disengaged
and does not turn.
There is a strong spring in this lever. Pull out firmly on the end of the lever
while moving it.
Power Feed Lever
The power feed lever locks the half nuts around the lead screw, which engages
the power feed.
The power feed is engaged when this lever is down and disengaged when this
lever is up.
Carriage Hand Wheel
The carriage hand wheel moves the carriage toward or away from the
headstock, depending on which way it is turned.
Use this hand wheel to position the carriage. Because this hand wheel moves
the carriage quickly it is not easy to use this hand wheel to move the carriage
while you are turning.
You cannot turn this hand wheel when the automatic feed is engaged.

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Cross Slide Feed Handle
The cross slide feed handle moves the cross slide across the ways. Use this
handle to advance the tool into the work and for facing cuts.
The dial on this handle indicates the relative position of the cross slide. The
graduated dial can be repositioned for convenience.
There are 40 divisions on the dial. Each turn of the handle advances the cross
slide 1 mm or approximately 0.040". The distance is actually 0.03937", an error
of a little less than 2%.
Compound Rest Feed Handle
The compound rest feed handle advances or retracts the compound rest. Use
this handle to advance the tool into the work.
The dial on this handle indicates the relative position of the compound rest.
The graduated dial can be repositioned for convenience.
There are 40 divisions on the dial. Each turn of the handle advances the
compound rest 1 mm or approximately 0.040". The distance is actually
0.03937", an error of a little less than 2%.
Digital Position Readout (Model 7350 only)
The HiTorque 7×16 Deluxe Mini Lathe has digital readouts on the compound
rest and cross slide.

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To use the digital readouts:
The readouts are easy to use. There are two buttons: ON/OFF and mm/inch.
Button
Function
ON/OFF
Press to turn on the display.
While the display is on, press to set the display to zero at the
current position.
Press and hold to turn off the display. Doing so extends battery
life. (The display shuts off automatically after about 30 minutes of
nonuse.)
mm/inch
Switches the display between millimeters and inches.
Chris’ Tip: These digital readouts do not account for backlash in the feed
screw. Always take your readings when you are turning the screw in the same
direction. This is not a problem on a lathe, because a single cut will only be
made in one direction—in for turning, and out for boring.
To replace the battery:
Each DRO uses a single CR2032 lithium battery (LittleMachineShop.com part
number 4292).
1. On the bottom of the display unit, squeeze together the two tabs and then
pull out the battery drawer.
2. Replace the battery and then slide the drawer in until it snaps shut.
Compound Rest Rotation
The compound rest rotates on the cross slide and you can position it at any
angle.
Position the compound rest so it moves parallel to the ways to make precise
facing cuts.
Position the compound rest at 29.5 degrees for cutting standard threads.

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To change the angle of the compound rest:
1. Using the compound rest feed handle, retract the compound rest until the
locking socket head cap screws are exposed.
2. Loosen the two socket head cap screws.
3. Turn the compound rest to the desired angle.
4. Tighten the two socket head cap screws.
Chris’ Tip: Use a protractor between the compound rest and the cross slide.
Don’t depend on the die cast or plastic markings on the side of the compound
rest.
Tailstock Locking Lever
The tailstock is locked into position on the ways by the tailstock locking lever
on the back of the tailstock. Raise the lever towards the vertical to tighten the
tailstock lock.
Tailstock Quill Hand Wheel
The tailstock quill hand wheel moves the tailstock quill in and out. Graduations
on the top of the quill show how far it is extended.
Retract the tailstock quill all the way to remove tools from the taper in the
tailstock quill.
Tailstock Quill Digital Position Readout (Model 7350 only)
The HiTorque 7×16 Deluxe Mini Lathe has a digital readout on the tailstock that
displays the quill position more precisely than the graduated markings on the
standard model. Operation of the tailstock readout is the same as those for the
compound rest and cross slide. See “Digital Position Readout (Model 7350
only)” on page 13.
Tailstock Quill Locking Lever
The tailstock quill locking lever keeps the tailstock quill from moving. Use the
tailstock quill locking lever to lock the tailstock quill in position when you are
turning between centers. Turn the lever clockwise to lock the tailstock quill,
and counterclockwise to unlock the tailstock quill.
Adjustments
Keeping your lathe in adjustment is an ongoing process. You should check all
the following adjustments when you set up your lathe and then periodically as
you use your lathe. Looseness in the carriage retaining plates or the gibs can
cause chatter when you are using the lathe. If you experience chatter, check
all these adjustments.

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Carriage
The carriage is held on the ways by two adjustable retaining plates that are
bolted to the bottom of the carriage.
There are several fasteners in the carriage retainers. The socket head cap
screws are used to adjust the position of the retainers. The setscrews and lock
nuts lock the adjustments in place.
To adjust the carriage retainers:
1. Remove the right lead screw mounting bracket.
2. Disconnect the apron by removing the two socket head cap screws through
the front of the carriage.
3. Slide the apron to the right and off the lead screw.
4. Loosen all the fasteners on both retainers.
5. Snug the socket head cap screws so the carriage can move, but without
play.
6. Snug the setscrews. Do not over tighten or you might break the retainers.
7. While holding the setscrews from turning, tighten the lock nuts.
8. Replace the apron.
9. Replace the right lead screw mounting bracket.
Cross Slide Gibs
A gib is a strip of metal placed between the bearing surface of two machine
parts to ensure a precision fit and provide adjustment for wear. The mini lathe
has gibs in several places, including the cross slide.
Carriage retainer

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To adjust the cross slide gibs:
1. Loosen the three lock nuts on the side of the cross slide.
2. Slightly loosen all three setscrews on the side of the cross slide.
3. Snug each setscrew equally. This will lock the cross slide in position.
4. Loosen each setscrew 1/8 turn to allow the cross slide to move.
5. While holding the setscrews from turning, tighten the lock nuts.
6. Test by turning the handle. Loosen or tighten all the setscrews the same
amount until the cross slide moves freely, but without play in the dovetail.
Cross Slide Nut
The cross slide nut is adjustable to remove free play from the cross slide feed
handle.
The three screws in the top of the cross slide adjust the cross slide nut.
The two outer screws tip the nut off horizontal to reduce the endplay in the
threads. The center screw locks the adjustment in place.
To adjust the cross slide nut:
1. Loosen all three screws.
2. Tighten the outside setscrews until you just start to feel resistance turning
the set screw.
3. Loosen the near set screw and tightened the center screw until you just
start to feel resistance turning the cap crew. At this point the bottom
threads of the nut should be touching the lead screw at the far end, and the
top threads of the nut should be touching the lead screw at the near end.
4. Tighten the front set screw.
5. Check the adjustment.
•If the feed screw is too hard to turn, loosen the front set screw a little
and then tighten the center cap screw.
•If the feed screw is too easy to turn and you have excessive backlash,
loosen the center cap screw a little and then tighten the front set screw.
Cross slide nut
adjusters
Cross slide gib
adjusters

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Compound Rest Gibs
The compound rest also incorporates a gib for adjustment.
To adjust the compound rest gibs:
1. Loosen the three lock nuts on the side of the compound rest.
2. Slightly loosen all three setscrews on the side of the compound rest.
3. Snug each setscrew equally. This will lock the compound rest in position.
4. Loosen each setscrew 1/8 turn to allow the compound rest to move.
5. While holding the setscrews from turning, tighten the lock nuts.
6. Test by turning the handle. Loosen or tighten all the setscrews the same
amount until the compound rest moves freely, but without play in the
dovetail.
Apron Position
The apron is adjustable to center the half nuts horizontally on the lead screw.
To adjust the apron position:
1. Loosen the two socket head cap screws that secure the apron to the
carriage. They are at the front edge of the carriage.
2. Engage the half nuts on the lead screw.
3. Tighten the two socket head cap screws.
Tailstock Position
The tailstock is adjustable from front to rear so you can align it with the
spindle.
Compound rest
adjusters
Apron adjusters

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To adjust the tailstock position:
1. Remove the 3-jaw chuck from the lathe spindle.
2. Put a 3 Morse taper dead center in the spindle.
3. Remove the tailstock from the lathe.
4. Loosen the tailstock adjustment cap screw.
5. Place the tailstock back on the ways.
6. Put a 2 Morse taper dead center in the tailstock quill.
7. Move the tailstock toward the spindle until the two centers almost touch.
8. Loosen the tailstock adjustment setscrews.
9. Move the upper part of the tailstock casting until the centers are aligned.
10.Place a steel rule between the two centers. The length of the rule should
be horizontal and the width vertical. Bring the centers together to hold the
rule in place.
11.Adjust the upper part of the tailstock casting until the steel rule is
perpendicular to the axis of the lathe. If the near end of the rule angles
toward the headstock, move the tailstock back.
12.When the tailstock is in the correct position, tighten the tailstock
adjustment setscrews.
13.Gently remove the tailstock from the lathe and tighten the tailstock
adjustment cap screw.
14.Replace the tailstock on the ways and check the adjustment.
Half Nuts
There are two adjustments for the half nuts. The half nut gibs take the play
out of the half nuts. The half nut closing limit stops the half nuts from closing
too tightly on the lead screw.
Tailstock adjustment
setscrew
Tailstock adjustment
cap screw

20
To adjust the half nut gibs:
•Tighten the three setscrews in the back edge of the apron to remove play
from the half nuts.
To adjust the half nut limit:
1. Loosen the lock nut on the bottom of the half nuts.
2. Adjust the setscrew until the half nuts close without binding on the lead
screw.
3. While holding the setscrew from turning, tighten the lock nut.
Lead Screw Mounting
The brackets that mount the lead screw can move slightly to ensure that the
lead screw does not bind in the half nuts.
To adjust the right lead screw mounting bracket:
1. Remove the tailstock by sliding it off the end of the ways.
2. Loosen the two mounting socket head cap screws on the right bracket.
3. Move the carriage as far to the right as possible.
4. Engage the half nuts on the lead screw.
5. Tighten the bracket mounting socket head cap screws.
6. Replace the tailstock.
To adjust the left lead screw mounting bracket:
1. Remove the change gear cover.
2. Loosen the locking nut on the change gear adjuster.
3. Loosen the two mounting socket head cap screws on the left lead screw
bracket.
4. Move the carriage as far to the left as possible.
5. Engage the half nuts on the lead screw.
6. Tighten the bracket mounting socket head cap screws.
7. Tighten the locking nut on the change gear adjuster.
8. Replace the change gear cover.
Drive Belt
The drive belt is a timing belt and should rarely need adjustment.