Prusa MK3 Y-Axis Belt Tensioner for Gates 20T Idler with 5mm Bore

thingiverse

Y-Axis Belt Tensioner for Prusa MK3. This is designed for a 20T Gates Idler with a 5mm bore. It's closely based on MattyVee's excellent design at https://www.thingiverse.com/thing:2786671. Items you'll need to make this: (1) Gates 20T idler with a 5mm bore (1) 4.95 mm diameter shaft that is 24mm long (the opening is 24.5mm, so 24mm works perfectly) (2) M3 x 20mm socket head cap screws - one for the pivot and one for the tensioner (2) M3 x 8mm socket head cap screws to mount the tensioner to the frame (4) M3 hex nuts - you can use flats or Nylock, but I don't see a reason to use Nylock nuts I included (2) .4 mm washers to center the idler. They're not necessary, but I prefer them. Note that the nuts are a tight fit, so they won't fall out. However, be prepared to put some effort into seating them, except for the tensioning nut slot. Print without supports and as oriented in the files, except the washers need to be properly oriented. I printed on standard Prusa settings - 2 perimeters, 20% infill - and it works fine. Feel free to print as you see fit.