Emvio Engineering gave me the opportunity to do a review on the Bondtech BMG Extruder.  I’ve been wrecking my brain on how to do this article, for me its a hard one.  This is because it was basically just plug and play on the Tevo Tornado.  I didn’t have to change any firmware or VREF to get it to work.  On my Tevo Tornado, the steps per mm on the extruder is 400.  Even though the recommended value from Bondtech is 415, 400 is working just fine for me.

Want to buy the Bondtech Bmg Extruder Check out Emvio’s website

To Change or Not To Change

In the future, I probably will change the steps per mm on the extruder to get a more accurate 3D prints, but for now I will stick to the 400.  For this article, I will print two calibration cubes to show you the difference between 400 and 415 steps per mm.  Some people might think that there wont be much of a difference, but we will wait and see.

Just for the fun of it, comment down below what value each picture of the calibration cube is…

calibration cube a
calibration cube b

Bondtech BMG Extruder Information


Two drive wheels grip the filament from each side, providing a powerful and reliable feed into the hotend.  From common materials like PLA and ABS, to flexible filament like professional Series Flex or Ninjaflex, the dual-drive gears of the Bondtech BMG can deliver a consistent flow of filament in either direct drive or bowden configurations.


The BMG is designed with a door on the side that holds one of the dual-drive gears. This door is closed with a spring-tensioned thumbscrew. This thumbscrew enables an exact tension of the drive gears for the proper hold on filament, with the ability to release the strain and simply load or unload the filament.  All you need to do is pull away from the extruder so that the spring will compress just enough to release the pressure on the material, letting you easily feed it directly into the hotend.


Bowden? Direct drive? The Bondtech BMG is constructed for either setup with a mounting slot on the bottom for a E3D hotend or a groove mount for bowden tubes.  The light-weight style of the BMG makes it good for direct drive configurations.  This is because it helps to reduce tool head weight.  Having a lighter tool head suggests that the printer can move quicker while not sacrificing exactness or print quality because of wobble.


  • Filament diameter supported: 1.75mm
  • Weight (without motor): 75g
  • E-step value: 415
  • Compatible stepper motor: Nema17 (5mm shaft)
  • Gearing: 3:1


  • Bondtech BMG Extruder
  • Thumbscrew tensioner
  • Interface gear (mounts on stepper shaft)
  • 3 mounting screws

Bondtech BMG Extruder
Bondtech BMG Extruder

Bondtech BMG Extruder

Bondtech BMG Extruder Installation

Installing the Bondtech extruder on to the Tevo Tornado was a very easy task.  It was as simple as 6 steps.. DONE!

All You Need To Do Is…

  1. Remove the titan extruder
  2. Take of the old gear from the motor
  3. Replace it with the new gear
  4. Place the motor back
  5. Place the extruder on top
  6. Put in your 3 bolts


Calibrating the Bondtech Extruder

Tevo Tornado Control Panel

You can do this a number of ways Control => Motion => Steps /mm => E Steps /mm and enter the value 415.  If your Tevo Tornado is setup for eeprom you can save your new settings if this E Steps do not help.  Head over to this article about Extruder Calibration

Here is what we printed using the Bondtech BMG. The 3D model that was used is the Fancy Skull By Kimbolt and the filament is Eryone Rainbow PLA 1.75mm.


So why do we like the Bondtech Extruder Compared to the Titan Extruder clone?  Its simple, it just works!  The easily adjustable tension coupled with the dual drive gives you flexibility to fine tune your filament tension.  This power house of an extruder just keeps puling

One thing I did notice, was when doing an atomic pull, do not do the pull through the whole extruder. What I do so it does not get stuck in the extruder, is pull the filament away from the nozzle.  Once its in the PTFE tube, I then would release the PTFE tube from the extruder.

Instead of pulling from the Inlet of the extruder, pull from the outlet.  This is to help prevent the filament from sticking in the extruder.  When you do a cold pull, the filament is usually larger at the tip.  So, if you pull from the PTFE tube side, this will take the thin side of the filament through the extruder resulting in an easy atomic pull and a unblocked nozzle.


Why Not check out our 3D Printer Deals Or to get a better description of atomic pulls have a look at Hotend Jams

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