Bondtech LGX Large Gears eXtruder is smarter, smaller, lighter







LGX Large Gears eXtruder

LGX Large Gears eXtruder

(3 customer reviews)

Each LGX® extruder is supplied with:

  • 1x LGX® feeder;
  • 1x Custom Nema17 25mm pancake stepper motor;
  • 1x Bowden Interface Plug (with threaded metal push-fit);
  • 1x Direct Drive Interface Plug (for Slice Engineering hotends);
  • 1x 2mm Hex Key (recommended tool);
  • 1x Product Line Information Brochure;
  • 1x Powered By Bondtech sticker.
  • 3x M3x30 mm Low Head screws;
  • 4x M3x18 mm Stud with 5mm Hex with M3x4 thread;
  • 30mm PTFE tube to use in the Direct Drive Interface Plug.

This extruder only supports 1.75 mm size filament.



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The Bondtech LGX® Large Gears eXtruder is the first of our filament feeders using Bondtech’s new Dual Drive Technology based on larger drive gears.

7 new features on a Bondtech eXtruder:

  • Larger drive wheels, for increased filament grip;
  • Filament pre-tension lever, for repeated results;
  • Multi-function interface socket, for tool or application quick swap;
  • Drive wheels’ maintenance windows, for easy cleaning;
  • Compact, light & symmetric design, for increased performance and compatibility;
  • Multiple mounting hole patterns, for easy and flexible setup;
  • A small step for a greener Future, craft boxes without bleaching & no coating.

You can read more about the new features by clicking here.


3D Printed Housing using PA12

The housing parts are professionally printed with nylon for maximum strength and precision and higher temperature resistance.

4 additional mounting points

Use the supplied studs to replace the 4 screws of the stepper motor and use them as additional mounting points.

Be aware the stepper motor threads are made of Aluminum, and they are delicate.
Don’t use too much Torque to tighten the studs.
Preferably use finger force only.

You can find these studs on the accessories bag in your LGX® package.

They have a M3 thread with 4 mm depth.

Freight Weight 293 g
Dimensions 10 × 8 × 7 cm


Do not connect a LGX® stepper motor to a printer's cable without checking the wires and pins of the connection cable.

Not all printers are ready for a direct connection with the LGX®. Some use stepper drivers with no protection and this may damage them.

Before connecting a LGX® to any 3D printer check if the connector pins are wired as shown below:

After start of service, if the LGX® is turning in the wrong direction, swap the top (or bottom) pair of wires to make a correction:

Extruder and Stepper Motor go together

Preferably, you should always use the extruder attached to the stepper motor when you mount it on a printer.

If you need to put a plate in between the stepper motor and the extruder please notice that you need longer screws, and the max supported thickness is 2.6mm.

This image below shows what screws are used on the LGX®, and the red ones are used to attach the stepper motor and extruder:

To use a plate in between the stepper motor and the extruder, you need to replace the stock M3x27 low head screws with the 3 M3x30 low head screws we send in the accessories bag, which are compatible with printer plates of thicknesses between 0.3 and 2.6mm.
Don’t use a plate in between without using the longer screws.

Technical Data Sheet

Pre-tension Lever Positions

The LGX Lever Positions

The LGX eXtruder is the first to present a pre-tension mechanism that includes an easy to use lever for users to release the tension or define it as one of 5 different settings.

Find below the illustrations and descriptions that show the available options.

Please note that filament made of different materials or made by different manufacturers may requires a slight different setting.

Position 0

When facing the LGX eXtruder push the lever all the way to the left.

Use it to load or unload filament without pressure from the drive gears.

Position 1

When facing the LGX eXtruder push the lever all to the left and then 1 position to the right.

Use it to work with rigid materials.

Position 2

When facing the LGX eXtruder push the lever all to the left and then 2 positions to the right.

Use it to work with semi-flexible materials
Shore hardness of ~95A

Position 3

When facing the LGX eXtruder push the lever all to the left and then 3 positions to the right.

Use it to work with flexible materials
Shore hardness between 85 and 95A.

Position 4

When facing the LGX eXtruder push the lever all to the left and then 4 positions to the right.

Use it to work with soft materials
Shore hardness between 75 and 85A.

Position 5

When facing the LGX eXtruder push the lever all to the left and then 5 positions to the right.

Use it to work with very soft materials
Shore hardness between 60 and 75A.

Hot Stepper Motor?

To use the LGX®, LGX® Lite or LGX® Lite Mirrored, run the stepper motor with currents between ~0.45 and ~0.65A.

This current interval is just a recommendation and it should be optimal to keep the stepper motor running with enough torque and low enough surface temperature.

Be vigilant regarding the stepper motor surface temperature.
Keep it cool enough to touch. Lower the current otherwise.

If the stepper motor is cool and loosing steps you need more torque.
In this case increase the current.

To adjust the LGX's stepper motor current use one of the following methods:

It is very hard to read the current being fed to stepper motors. To determine that current we rely on the Vref value. The Vref value is a voltage reference measured in VDC that can be read using a multimeter. It helps us setting the current output of the stepper motor driver.

Different 3D printer mainboards use different stepper motor drivers. Each type of stepper motor drivers has its own formula to calculate the required Vref to get a specific current.

You can learn how to adjust the Vref by watching the video or by following this guide as example:

Lowering current on Ender-6

If your printer doesn't have DigiPOTs, and in case you don't have a multimeter to visualize the Vref you may still adjust the current fed to the LGX stepper motor by trial and error.

Use the analog potentiometer (inside yellow ring)next to the extruder's stepper motor driver (below the heatsink inside the red ring), and turn the potentiometer a few degrees at a time.

Rotate it counter clockwise to lower the current, or clockwise to increase it.

Between each iteration, use the printer and check if the stepper motor is not getting hot neither it is loosing steps.

Lower current if stepper motor is too hot to touch.

Increase current if stepper motor is loosing steps.

DigiPOTs are digital potentiometers which resistance can be varied by digital communication instead of turning a knob, like seen above.

On a 3D printer with a mainboard carrying DigiPOTs, you may use the user interface of the unit (if that feature is available) or even Gcode commands to set the current of the different stepper motors.

On RepRap units with DigiPOTs, the M906 command may be used to change the Extruder stepper motor current M906 Ennn, where nnn is the amount of milliamps desired.

Marlin also uses a similar command. M906 Ennn sets the current on TMC drivers. On stepper motors with other drivers and DigiPOTs, you may also set the current in milliamps using the command M907 Ennn

Product Videos


The LGX extruder – How It’s Made

LGX Webinar

STEP Files To Download

Click the links below to download STEP files with simplified geometries of each available setup.

LGX™ Interface Plug geometry.

3 reviews for LGX Large Gears eXtruder

  1. nzzane (verified owner)

    Great addon for my CR6-SE, definitely worth the upgrade.
    Super solid build

  2. Mike O’Brien (verified owner)

    I converted a home-built CoreXY printer from an older QR-based Bowden setup with E3D V6 hot end to an LGX. It’s lighter and smaller, allowing me to access more of the (400×400) bed surface. Due to the light weight I was also able to redesign the X axis from dual 10mm rods to a single linear rail. Print quality is excellent using the Slice Engineering Copperhead extruder.

  3. madchip (verified owner)

    work perfectly on anycubic predator, just twist wire 1 and 3

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