Bearing

A basic roller bearing that can be easily printed and used.Dimensions: 39mm X 8mm X 18mm To free the cylinders you might need to push the middle part of the bearing down and use a bit of force. If the rollers are still not free you can try using a knife but this should not be required. If the knife doesn't work then your printer may not be able to print these clearances. Boost MeBoosting helps me out and makes me more motivated to make more models!