Rep Rap Warehouse/ Makerbot spool roller

You don't need any washers, it's spaced properly to use the bearing for everything. You'll have to print the left side and right side separate if you have a smaller machine. Uses standard 608 skate bearings. Clean up the frame hole with a 5/16 inch drill bit for a perfect fit. It will print on a 200 X 200 mm bed if you plate it properly and keep the skirt close. Check out my other designs for some interesting stuff that prints well.