Linear Bearing

These are used as the Y-axis on my Custom 16inch by 16 inch Prusa Printer. These are under the bed. Instead of expensive hardened steel rods (expensive) for the Y axis I designed these for `1/2 inch square tubes (cheap)

4 22m x 7mm Skate Board Bearings
4 693zz bearings
2 3mm x 8mm bolts