GT2 Toothed Idler for Ender 3

thingiverse

A user on the Creality Facebook page posed a question about toothed idler wheels for the Ender 3, prompting me to create one that can be printed. Other toothed idlers available here on Thingiverse use an involute engagement profile, which I believe is incorrect for this application. This is because we are dealing with a belt meshing with a gear, not two gears engaging. To rectify this situation, I designed the part with the correct engagement profile and sized it specifically to fit over the idler pulleys on an Ender 3. Update (5/1/18): Upon examining other printers, I reduced the diameter of the pulley to provide a little wiggle room for variation in belt length. I also corrected an error with how I constrained the tooth profile that was affecting the pitch.