Bader III idler wheel camber question.

[anvilring]

I have come to realize with some help from others, that my 6-in idler wheel has lost its crown over time and is the reason my belts are wandering about like besotted sheep. What curvature (convexity?) would you put on this wheel? My friend has a lathe and can do it for me, but I need to tell him where to start.

 

[bondoo7]

The crown should be between 1-1.5% from the wheel width, more of that and you'll deform the belt in the middle without any benefit. My idler has 70mm width(2.75in) and the crown 1.5% translated to 1mm height and tracking is spot on.

 

[anvilring]

Thank you!