I used a plywood deck to prototype this device. MFRshooter heavily influenced this design. I used ansi # 25 chain and sprockets, my skateboard wheels are 2.55 inches tall and I glued stainless steel shaft collars into the wheels on each side. The holes in the wheels are for the Allen key to reach the set screw. I also have a programmed power switch for 1,2,4 or 8 hours.