Losmandy GM811 DEC worm block pivot tensioner

thingiverse

This part fits the Losmandy GM811 with tucked motors. Due to production tolerances, the GM811 declination axis left side worm block pivot post can be a slightly loose fit in the hole. This can allow the entire worm assembly to shift sideways during tracking and / or in the presence of wind gusts. Even a tiny amount of movement here is magnified by the geometry of the worm and worm wheel and can be a major source of backlash and wind susceptibility. This device installs in place of the stock shoulder washer on the left side worm block pivot. The nylon screws press against the front edge of the baseplate and force the worm block pivot post against the front side of the pivot hole, preventing sideways motion and reducing backlash. The wedge is printed with 8-32 threads but you may have to chase the threads with a threaded rod or a 8-32 tap to clean them up enough for easy, smooth operation. You will need two 8-32 nylon bolts, a stainless 10-32 X 3/4" hex head bolt (the stock bolt is too short) and a #8 washer. Everything should be available at a decent hardware store. Install this device in place of the stock shoulder washer with the nylon screws bearing on the front edge of the baseplate. Tighten the pivot bolt until not quite snug and adjust the two nylon screws evenly until they develop enough force to prevent sideways movement but still allow the worm assembly to pivot. Because they are nylon, they will not damage the anodization.