Prusa Bear Y belt tensioner

thingiverse

On my Prusa MK2S, a Y belt tensioner had already been installed, allowing for easy adjustments to the tightness of the Y belt. When installing the Prusa Bear upgrade, a new method for this was needed. After searching around, a setup from the MK3 caught my eye, but it wouldn't fit the Bear frame, so a redesign was necessary. The redesigned piece mounts upside down compared to the original, and a modification was made to the space reserved for the idler pulley. I downloaded the version of the object that matched my toothed 20T pully. To ensure the pulley didn't touch the sides, the opening was enlarged and enough room was left for the pulley and two 3mm flat washers. The opening is now 10mm wide. For more details about the hardware required, refer to the original part. A 25mm bolt was used for the tension adjuster, but a slightly different length may be needed depending on the belt's length. In the original piece, a nyloc nut was inserted into the adjusting arm, so it was moved to the back of the main bracket instead. The adjusting bolt now goes through the arm and into the fixed piece. The adjustment range is somewhat more restricted, but there's still plenty of room for adjustments. My original belt turned out to be slightly too short, so it was replaced.