Replaced the stock double idler assembly on my Greenspeed Aero trike with a used single idler fabricated from some unknown plastic. After a number of miles, the used idler developed even more chain side-plate chatter marks in the rolling surface than it originally had. Accordingly, it was getting noisier and noisier. I know that Delrin is used by some idler manufacturers, so purchased a 2.75" x 12" cylinder of an unknown grade, and fabricated a new idler on my metal lathe. Cut a V-groove in the center of the rolling surface and installed a Nitrile O-ring to eliminate chain noise. Rode 42 miles on yesterday's Plano East Side Ride and couldn't hear any idler noise. Hope the idler will be as durable as a Bacchetta plastic idler. Should have read the MSDS sheet for Delrin, before I machined it - fumes and dust can be hazardous. Will take precautions the next time I machine an idler.
DuPont Delrin cylinder purchased off of E-Bay
Cutting 15-mm thick disk off of cylinder with carbide blade chop saw
Boring hole in chucked-up disk to receive 8-mm skateboard bearings
Cutting chain recess in disk
Completed idler
O-ring installed in center of chain recess rolling surface
Installed idler