Self centering idler bearing for Y-axis belt.

thingiverse

I tried to adjust the belt's path along the Y-idler and I didn't enjoy trying. Making it run absolutely straight with small pieces of paper on a metal printer just felt awkward. This reminded me of classic crowned pulleys. They are crowned in the middle, causing the belt to stay perfectly centered. For a clear explanation, take a look at this webpage: http://woodgears.ca/bandsaw/crowned_pulleys.html To make my bearing into a crowned idler, I used a belt sander to carefully create a beveled edge. Mount it on threaded rod first then gently rub away at an angle roughly more than a third of the diameter of your bearings until they are both smooth and equal.