Summary 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. Instructions I printed it.