MPCNC Double Belt

thingiverse

************** Update: After using my MPCNC with the double belt for over one year, the glued belt started to detach from the angle iron. I used this opportunity to switch to a single belt design. I haven‘t noticed any difference so far, except that finding the right belt tension is easier with a single belt. Maybe machines with a longer belt length will benefit more from the double belt. But as long as you don’t feel adventurous, I would suggest to stick with the original MPCNC for simplicity. If you installed the double belt and want to switch to a single belt as well, you can find a drop-in replacement for the belt tensioner here: https://www.thingiverse.com/thing:3875362 ************** This thing is WIP and there are currently no building instructions! The parts are for the 25mm version of the MPCNC. By interlocking a belt with a second belt it is possible to reduce the length of the tensioned belt and therefore reduce stretching. The parts were designed for a 15mm wide belt, but other sizes should work as well. For more information check out my build series: https://youtu.be/IjwD5smOt38 Parts you need: 4x Corner_Top 8x Corner_Middle 8x Corner_AngleSupport 4x Corner_Bottom 4x Corner_Clamp 4x Roller_Backplate 4x Roller_Frontplate 2x Roller_modified 2x RollerM_modified 4-8x Tensioner 8x Beltclamp_Bottom 8x Beltclamp_Top 4x 20x20x3 angle iron (same length as your x-/y-conduit) 8x M8-70mm (only needed when using a belt wider than 10mm) 16x M6-75mm screws (DIN 912) + nuts 8x M4-20mm screws (type doesn't matter) + nuts 8-16x M3-30mm (depending on your amount of tensioners) 16-24x additional 608 bearings (depending on your amount of tensioners) You still have to print all parts from the original MPCNC, EXCEPT: Roller RollerM RollerPlate Everything that has a "Corner" in its name Roller and RollerM are modified because there is no space for a nut below the angle iron. So you have to tap the central bearing hole and also use a shorter screw. Changelog: 1-19-2019: Removed countersunk on Corner_Top, M6 screw length adjusted to 75mm 9-23-2019: Description updated 9-29-2019: Added a bit more clearance on Roller_Backplate 12-20-2019: Parts list updated (added 8x M8-70mm)