This Y bracket for a prusamendel can (also) be used if you want or need your belt to run very close to your stepper. It is clipped onto your frame then bolted in and secured by the washers so you don't need to take your frame apart to get it on and off.My steppers have machined pulleys fixed on them with a length of 14.5mm, but the teeth only go untill 10,5 mm.The pulleys have a diameter of 9.7mm with 11 teeth and a 3mm pitch. when your diameter is much bigger the belt cannot be so close to the stepper because it will not have enough clearance.You can use this with a nut less than the standard design. I have the following on the rod: a nut, small washer, Y bracket, small washer, big washer, small washer, bearings, small washer, big washer, nut. To avoid a collision with my bottom print plate I have cut a bit out of the plate as you can see on the picture taken from the bottom of the reprap.I have uploaded an stl file both with and without rounded edges. furthermore an inventor file. My bracket was printed on a commercial machine with a second extruder for the support material.