Fabtotum BMG Extruder Bracket Clamp

thingiverse

If you've got a Fabtotum, finding a great extruder for the machine is one of the first things you need to do to get amazing prints (that and replace the plastic JHead). The Bondtech BMG or in this case BMG clone is an excellent extruder for the Fabtotum. Quick with lots of torque, it's by far one of the best investments for this machine. This is a bracket that attaches to the filament spool area of the Fabtotum. It uses the already existing standoffs inside the plastic shell. To get this working correctly and optimally, you need to follow a few steps. 1. You must print this in PETG or a similarly flexible filament because PLA may break. You need to spread the "ears" of the bracket apart to slide in the stepper if it has a socket at the stepper base. 2. After printing, drill out the screw holes with a 3mm bit. 3. Assemble your BMG extruder - you probably already did that, but that goes without saying. 4. Slide the extruder and stepper into the bracket. 5. Thread the screw through the "ears" so the bracket tightens around the stepper. 6. Tap (with a 3mm tap) the plastic of the Fabtotum case - very important. The plastic is hard and can't be screwed in easily, so you'll want to tap it or use self-threading screws or the best option: brass inserts. Inserts are probably the right way to do this. 7. Cut some cork washers so the stepper won't vibrate/resonate into the plastic Fabtotum case. 8. Cut three pieces of 1/8" thick cork, each the size of the rear of the stepper bracket - this helps deaden the stepper vibrations at the back of the bracket. 9. Attach the two left-hand screws first, making sure your cork is between the bracket and the Fabtotum case; then attach the right-hand screw. 10. Make sure to place the cork behind the extruder bracket. Voila! You're done! With a 1.8-degree stepper, my BMG calibrated steps are about 416-418/mm. I've done this conversion on two Fabtotums and both are printing amazingly. Enjoy.