Self centering idler bearing for Y-axis belt.

thingiverse

I did not like trying to make the belt run absolutely straight on the Y-idler. Using little pieces of paper on a steel printer just seemed wrong! This made me think of old fashioned "crowned pullies". They are "crowned", higher in the middle, and that makes the belt stay centered. For a nice description, look here:http://woodgears.ca/bandsaw/crowned_pulleys.html I belt sanded the bearing, to make a "crowned bearing" to use as an idler. You have to be careful, but once it us done right, it works like a charm. Instructions Mount the bearing on a piece of threaded rod, then grind it on a belt sander to make a nice bevel, a bit more than a third of the width of the bearing. Flip the bearing over, and grind the other side at the same angle. Holding the bearing on the sander as shown in the "children's drawing" lets it rotate, and gives a nice, symmetrical grind. (Be very careful to make the two grinds identical!) Mount it on a piece of 8mm smooth rod, not a threaded rod or a piece of printed plastic!