Simple Y-axis Tension Arm for Prusa Mendel

thingiverse

Easily fabricated, this part is a 50mm long bar with two M8 holes. One end features a 608 bearing and the other fits on the lower front rail next to the motor mount. Install it as shown in the photo. Fender washers aren't necessary unless your belts are misaligned, but use thin washers for free bearing rotation. After fitting, adjust the angle to remove belt slack (avoid tightening too much to prevent increased load on the Y motor), then fasten with the right-hand nut. This helps eliminate Y-axis backlash. For a hassle-free installation, I used a locking M8 nut on the bearing end and an approximately 36mm M8 bolt from my spare parts. If you lack a suitable bolt, opt for a short M8 threaded rod with extra nut and washer. Include two thin M8 washers for the bearing side. Ensure the bearing rotates freely before attaching to the printer. At the other end, slide an M8 washer onto the right-hand Y motor nut, followed by the part, another washer, and finally the nut. Adjustments require only this last nut. The required components include: 1 RP printed part, 1 M8 bolt (at least 32mm), 4 M8 thin washers, 1 M8 locking nut (or two nuts tightened together), 1 M8 standard nut, and 1 608 bearing.