Sainsmart Coreception 300 Belt Tensioner

thingiverse

A Sainsmart Coreception 300 belt tensioner. I never needed it with the factory belts, but once I replaced the drive system with larger pulleys and steel belts, I needed a belt tensioner. You'll need 2x 608ZZ flanged (preferable) bearings. Print 1 tensioner and 1 tensioner bracket (the thing that moves the bearings in). I used 2x M5x40mm screws and nuts to attach the bracket to the tensioner. The design calls for 2x M5x20mm screws and nuts to secure through the frame, however the picture only shows one (I messed up the 2nd hole). I recommend using a vise to clamp the bracket to firmed on the frame (should be flush with the front), and another vise on top/bottom of the bracket to prevent the clip above/below the frame from drifting vertically. Use a drill press instead of guessing flush if you want to be extra precise. When fitting the bearings, make sure to leave a tiny gap between the two bearings so they don't rub on each other and leave enough space for a full GT2 belt.