Larger Idlers for FT-5

Designed this to fix the squeaking once and for all. The original bearings look like SMF85ZZ and are extremely thin, resulting in tiny balls that just can't take the load (8 Kgf rating?). Flanged 624 bearings much larger, and have room for larger balls resulting in a rating of 49 Kgf. I get them from eBay for about $1 each, and for this build you **do need the flange version** to keep the belt in line.

Source at https://cad.onshape.com/documents/ad4e3fb2856fd383e6ff196c/w/3b02a236f7d492db0