Losmandy GM8 Belt Drive Stepper Motor Mount

thingiverse

UPDATE Over the past few days, I've been working on this design and made some changes. There are now stepper mounts for both RA and DEC, and a single belt cover design that fits both stepper mounts. In addition, on the inside of the cover, there is a insert for an additional F625ZZ flange bearing. The shaft can now extend beyond the 60-tooth pulley and into the bearing in the cover, to provide additional support to the pulley shaft. This is a NEMA 17, belt-drive, stepper motor mount for the Losmandy GM8 mount. As I built it, I used a 15-tooth gear on the motor and a 60-tooth gear on the 5mm shaft, providing a 4:1 reduction. My goal in designing this was to prototype a design that I would ultimately machine from aluminum. While this is still the case, and I will be having these machined, I see no reason that, if printed from ABS/PET-G or Nylon, that theses would not work in the long term. I would not print them from PLA, and expect anything but a short term prototype. I designed this motor mount for use with the [OnStep telescope motion control system](https://onstep.groups.io/g/main/wiki/home). Its a very versatile system and capable of controlling just about any telescope you could imagine. This is designed in Fusion 360, and I've included STEP cad files if you should need them. You can look at the RA 3D model [here](https://a360.co/2RkfZts), and the DEC 3D model [here](https://myhub.autodesk360.com/ue29882e51/g/shares/SH919a0QTf3c32634dcf1146410b25a5d98f). Formats other the STEP can be downloaded form these links. I used the following: [1x 15-Tooth GT2 Gear](https://www.ebay.com/itm/2pcs-GT2-Aluminum-Timing-Pulleys-15-Tooth-5mm-Bore-for-RepRap-Prusa-3D-Printer/263570210647?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649) [1x 60-Tooth GT2 Gear](https://www.ebay.com/itm/GT2-Timing-Belt-Pulleys-60-Tooth-60T-5mm-Bore-for-RepRap-Prusa-Mendel-3D-Printer/263430555628?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649) [1x 200mm GT2 Loop Belt](https://www.ebay.com/itm/GT2-Timing-Belt-Annular-Loop-Cogged-Geared-Rubber-6mm-Width-2mm-Pitch-200-2GT/142603517023?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649) [ 2x F625ZZ Flange ball bearings](https://www.amazon.com/gp/product/B07MKFGS8Q/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1) You would also need a 5mm shaft for the 60-tooth gear. The one in the design is 40mm and should be fine.