Anet A8 X belt holder and spring tensioner

thingiverse

I began to rebuild my Anet A8 printer, starting with the X belt holder and tensioner. To assemble this crucial component, I needed one M5x50mm bolt, one M5 lock nut, and a spring with an outer diameter of less than 8mm and an inner diameter of more than 5mm - the same type used for 3D printer beds, commonly available in packs on eBay. First, I attached the belt to the tensioner by threading it through a small rectangular hole and creating a loop. I then pressed the end of the belt against its teeth, making sure they were interleaved. Next, I pulled the other end of the belt, allowing it to carry the end out while keeping the loop on the opposite side in place. To secure the belt, I wrapped one end of the loop around an M3 bolt, which could be threaded through the loop later if needed. The other end of the loop was then wrapped around a printed 3mm cylinder. Once assembled, I attached the tensioner to the X carriage and adjusted the M5 bolt's rotation to set the desired tension. At some point, the movement would cease as all motion would be absorbed by compressing the spring. The video demonstrating this working tensioner can be found at https://youtu.be/mTAAGxeYjeE.