Timing Belt Y MXL, Printrbot Simple V2

thingiverse

This text is for Simple V2 w/o String tension ordered before 10/23/2013. For models with string tension, visit http://www.thingiverse.com/thing:220484. Motor mount and tie bar are identical on both MXL designs. The author experienced difficulty maintaining consistent traction with the string drive Y-axis and decided to design a positive drive. Key features of the new design include a timing belt drive, a bolt-on solution that doesn't require machine modification, and the ability to revert back to string drive if needed. After over a week of non-stop use without issues, the author shares the design. Comments, concerns, and suggestions for improvements are welcome. Note Update 1: be cautious not to over-tighten the belt; a picture of the author's quick fix is included in the gallery. A link bar to tie bearings together will be added soon, using M3 x 22mm screws. Update 2 offers two files: Bearing Tie Bar for higher tension without misalignment and Motor Plate Option A for stronger bearing supports. An updated drawing shows the link bar placement. Assembling the timing belt pulley and bearings is tight but doable, with bearings centered on the pulley. The upper edge of the wooden slot may need sanding to avoid rubbing set-screws. The pulley sits on the motor shaft's end, although no issues have arisen so far. A 5mm drill bit (28255A39) from McMaster Carr was used.