LittleMachineShop.com HiTorque 7500 User manual

The premier source of tooling, parts, and accessories for bench top machinists.
HiTorque 8½×20 Bench Lathe User’s Guide
Model 7500 •Model 7550 Deluxe
from LittleMachineShop.com

2
© Copyright 2022 LittleMachineShop.com.
All rights reserved.
Written by Chris Wood of LittleMachineShop.com
Revision 3, October 2022
LittleMachineShop.com
https://www.littlemachineshop.com
396 W. Washington Blvd. #500, Pasadena, CA 91103
[e-mail]•[phone]

Contents
Introduction .......................................4
Specifications......................................4
Safety Considerations ............................5
General Safety .................................5
Lathe Safety ....................................5
Electrical Safety ...............................5
Machine Safety .................................6
Features ............................................7
Front View ......................................7
Accessories.........................................8
Cleaning ............................................8
Mounting Your Lathe .............................8
Lathe Controls.....................................9
Motor Controls..................................9
Carriage and Cross Feed Controls ......... 10
Tailstock Controls............................ 13
Bluetooth DRO (Model 7550 only) ............ 14
Using the app ................................. 15
Axis detail settings .......................... 15
Absolute versus incremental coordinates 16
Points and workspaces ...................... 16
Tools ........................................... 17
Adjustments ..................................... 17
Carriage ....................................... 17
Cross Slide Gib ............................... 18
Cross Slide Nut ............................... 19
Compound Rest Gib.......................... 19
Compound Rest Nut ......................... 19
Apron Position ................................ 19
Tailstock Position ............................ 20
Half Nuts ...................................... 21
Drive Belt ..................................... 21
Maintenance ..................................... 22
Cleaning ....................................... 22
Lubrication.................................... 22
Chuck ............................................. 23
Changing Chuck Jaws........................ 23
Mounting Work in a 3-Jaw Chuck.......... 24
Tool Bits.......................................... 24
Grinding Tool Bits............................ 25
Adjusting Tool Bit Height ................... 26
Turning ........................................... 27
Manual Turning............................... 27
Turning with Power Feed................... 27
Facing ............................................ 28
Facing with Power Feed .................... 28
Turning Angles .................................. 29
Threading ........................................ 29
Change Gears................................. 30
Change Gear Tables ......................... 32
Making Left Hand Threads.................. 33
Tool Bit ........................................ 33
Compound Angle ............................. 34
Setting the Cutting Tool .................... 34
Threading Process ........................... 35
Common Accessories ........................... 35
Quick Change Tool Post..................... 36
Indexable Turning Tools .................... 36
4-Jaw Chuck .................................. 37
Faceplate ..................................... 37
Live and Dead Centers ...................... 38
Steady Rest and Follower Rest ............ 38
Parts Diagram: 7500............................ 40
Parts Diagram: 7550............................ 42
Parts List ......................................... 44
Wiring Diagram.................................. 47

4
Introduction
This user’s guide covers care and operation of the LittleMachineShop.com HiTorque 8½×20 Bench
Lathe. Be sure to read and understand the safety guidelines presented in this book before using
your lathe.
The HiTorque 8½×20 Bench Lathe is available in two models:
•Model 7500 is the standard version.
•Model 7550 is the deluxe version. It includes all the features of Model 7500 and adds:
oDigital position readouts (DRO) on the carriage, cross slide, compound rest, and
tailstock
oQuick change tool post set (QCTP) with five tool holders
oCompound rest modified to better accommodate the QCTP
oAnodized aluminum hand wheels and chrome knobs and levers
oFull length heavy duty splash guard
Chris’ Tip: You can upgrade your Model 7500 lathe with the following items available from
LittleMachineShop.com:
•Part number 5497: Digital position readout (carriage, cross slide, and compound rest)
•Part number 5513: Android tablet display
•Part number 5880: Digital position readout (tailstock)
•Part number 2280: Quick change tool post set, AXA
•Part number 4914: Compound rest top (required for AXA QCTP)
•Part numbers 4162, 4165, 2104, 2145: Chrome hand wheels and handles
Installation of these components creates a machine that functions like a Model 7550 deluxe lathe,
although it will have some cosmetic differences.
Specifications
Swing over bed
8.5" (215 mm)
Swing over
saddle
4.6" (118 mm)
Distance
between centers
20" (510 mm)
Cross slide travel
3.9" (100 mm)
Compound rest
travel
2.8" (70 mm)
Spindle through
hole
0.8" (20 mm)
Spindle taper
#3 Morse taper
Tailstock taper
#2 Morse taper
Spindle speed
100–2000 RPM
Range of threads
3–100 TPI; 0.25–5.0 mm
Longitudinal
power feed rates
0.0018" (0.045
mm)/revolution
0.0049" (0.126
mm)/revolution
Cross slide power
feed rates
0.0007" (0.019
mm)/revolution
0.0019" (0.048
mm)/revolution
Power
requirements
120 V 60 Hz 12 Amps
Spindle motor
output
1.34 hp (1000 Watts)
Machine weight
220 lbs (100 kg)
Overall
dimensions
40" x 22" x 16" (1010
mm x 550 mm x 400
mm)

5
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 bench 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 bench lathe is a small lathe. Don’t attempt jobs that are beyond its capacity.
•Check the work piece 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 work pieces
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 work pieces 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.
•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.

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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 work pieces 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.
•Make sure the machine is on a flat, level surface that can support the weight of the machine
plus fixtures, vise, and work piece.
•Clamp work securely. Cutting forces are significant and can turn work pieces 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.

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Features
Front View
1. Motor controls (for details, see “Motor
Controls” on page 9)
2. Headstock
3. Chuck
4. Carriage
5. Cross slide
6. Tool post
7. Compound rest
8. Tailstock (for details, see “Tailstock
Controls” on page 13)
9. Change gear cover
10. Bed ways
11. Apron (for details, see “Carriage and
Cross Feed Controls” on page 10)
12. Lead screw
1
2
3
4
5
6
7
8
9
10
11
12

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Accessories
The following accessories come with the HiTorque Bench Lathe.
•#2 Morse taper dead center
•#3 Morse taper dead center
•Change gears (for details, see
“Threading” on page 29)
•Outside jaws for the 3-jaw chuck (for
details, see “Changing Chuck Jaws” on
page 23)
•Chuck key for the 3-jaw chuck
•Open end wrenches: 8 x 10 mm, 14 x 17
mm, and 17 x 19 mm
•Hex wrenches: 2.5, 3, 4, 5, and 6 mm
•Mounting bolts and washers
Cleaning
Your lathe will arrive coated with grease to protect it from corrosion during shipment. Follow this
procedure to remove the grease:
1. Wipe most of the grease off with rags or paper towels.
2. Clean the surfaces with mineral spirits (paint thinner).
3. Coat the surfaces with oil.
See “Lubrication”on page 22 for specific recommendations for lubricants.
Mounting Your Lathe
Many people purchase a stand or chip tray for the HiTorque Bench Lathe. The machine bolts right
to these with the cap screws that are furnished. You might need to unbolt the motor to install the
two bolts on the back of the headstock.
You can also bolt your lathe to your workbench. The following diagram shows the holes required.

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Mount the lathe to the workbench with M8 (or 5/16") bolts. Use fender washers on the underside
of wooden benches to prevent the bolt heads from pulling through. You might need to unbolt the
motor to install the two bolts on the back of the headstock.
If you have the chip tray, its mounting dimensions are shown below.
Lathe Controls
Become familiar with the controls used to operate the lathe before you use the lathe.
Motor Controls
1. Power switch
2. Emergency stop (E-stop) switch
3. Start/stop button
4. Spindle direction button
5. Speed control knob
6. Spindle speed readout
6
5
4
3
1
2
14.41" (366 mm)

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Power Switch and Emergency Stop (E-stop) Switch
The green power switch enables input power to the speed control circuit board. The red E-stop
switch disconnects the power.
Turn the power off when you are not using the lathe.
Start/Stop Button
The Start/Stop button illuminates and starts the spindle when pressed while the power is on. The
spindle runs at the last set speed. Press the button again to stop the spindle. Use this button for
normal operation of the lathe.
Spindle Direction Button
The spindle direction button controls the direction the spindle turns. After turning on the power
and pressing Start, the spindle turns in the forward direction—the direction used for normal
turning. Press the button to toggle between forward and reverse directions. The button
illuminates to indicate reverse direction.
You can change the motor direction at any time and at any speed that safety allows. The motor
will make a controlled change of direction.
Speed Control Knob
The speed control knob adjusts the spindle speed.
Spindle Speed Readout
The spindle speed readout shows the speed of the spindle in revolutions per minute (RPM). It also
indicates the direction of turning, forward or reverse.
Using the Motor Controls
Use the motor controls to turn the spindle.
To power up the lathe:
•Press the top half of the power switch. The spindle speed readout illuminates.
To start the lathe:
1. Press the start/stop button. The button illuminates and the spindle turns.
2. If you want the spindle to turn in the other direction, press the spindle direction button.
3. Use the speed control knob to adjust the spindle speed.
To stop the lathe:
•Press the start/stop button. The lathe retains the speed and direction settings so that the next
time you start the lathe, it resumes at the same speed and direction.
To stop the lathe in an emergency:
•Press the red E-stop button.
Carriage and Cross Feed Controls
You can power the carriage, you can power the cross feed, and you can thread with the HiTorque
Bench Lathe.