Promega CoreXY Belt Tensioner

thingiverse

Check out this updated remix by user TheBum at https://www.thingiverse.com/thing:3409417. This is a fantastic, detailed method to tighten the XY belt on the Promega giant printer, but it can also be applied to other machines. Fusion code included, so feel free to modify as you see fit, makers! It requires some hardware, but makes subtle tightening incredibly easy. You will need: A 1/4" or M6 nut and a 1.5" long bolt (the tensioner bolt and nut) Two 1/2" or 12mm long M4 or 5 screws (to attach the knob bracket to the Promega bracket) Four 12MM long hexagonal offset posts with an M3 thread You can reuse four M3 Nema motor screws, which are about 12mm long This mod fixes a problem I was having where unscrewing the motor screws sometimes loosened the round offset posts where they met the motor instead of on top. The hex posts are registered in the bracket to stay put. Also, the knob tensioner is elegantly simple. No support needed. Assembly: Screw the four hex offsets into your Nema. Press the motor bracket onto the bolt recess facing left as you look at the machine from the front. Mount with the four M3 Nema motor screws from on top. Make sure the knob fits snugly and turns smoothly in its slot. Insert the 1/4" or M6 nut into the nut slot. Thread the tensioner bolt through the knob and nut. Use the two M4 screws to secure the knob bracket to the Promega motor bracket. To tighten, simply loosen the four top screws as normal and hand-tighten with the knob. Tighten the top screws when the tension feels nice and snug.