Prusa MK3, MK2S X-Axis Belt Tensioner

cults3d

I faced a challenging experience adjusting the belt tension on my MK3 printer during assembly. The rotating stepper motor provided limited adjustment options, making it difficult to achieve the desired tension. Additionally, accessing and tightening the belt on the X-Axis carriage after assembly proved to be a frustrating task. To overcome these issues, I designed a simple mounting plate that attaches to the motor and features slots for easy belt tightening. The plate is assembled onto the X-Axis motor using four M3 x 10mm screws from my spare parts bag. Three square M3 nuts are installed in the slots of the mount, allowing for loose assembly. A screwdriver provides leverage between the motor and frame to secure the belt tightly before fully tightening the three screws. I also rotated the pulley on the motor by 180 degrees to align it with the slot inside. Update 1/22/18: One user who fabricated this MK3 bracket encountered a similar issue, requiring an increased center diameter of 1.0in to accommodate their stepper motor. The original bracket STL features a center locating diameter of 22mm, which matches my MK3 stepper motor. I created an additional bracket with a 1in center diameter for users facing the same challenge. Update 10/30/18: I was informed that this design is incompatible with the new MK3 X-Tensioner feature. Unfortunately, it cannot be used simultaneously with this design.