Parametric idler pulley
by whosawhatsis, published
This is a parametric idler pulley for use with a bearing and a timing belt. This is based on Erik's suggestion (here: http://www.thingiverse.com/thing:3616 ) that Huxley should have proper idler pulleys rather than bearings with mudguard washers. Included are STLs for a 623 bearing with a 5mm belt (for Huxley), a 624 bearing with a 5mm belt (for Mendel), and a 608 bearing with 6mm belt (for makerbot).
My extruder needs a new motor, so I haven't tested this.