Crank arm which fits onto LEGO (R) Technic cross-shaped axles. When assembled correctly, the handle spins freely on the M3 screw without binding. SCAD file provided so you can make a different crank arm length, handle etc. It took me 8 iterations to get the "+" shaped socket to be a snug friction-fit on the axle without being too stiff, but the file has been tuned for my printer (UM2, PLA at 20 mm/s, 223 C) and may need adjustment for a perfect fit with any other printer.Print out one each crank arm and round handle. The assembly uses one M3 screw (25mm long), two M3 nuts and two M3 washers. One nut is captive in the crank arm on the handle side, the other nut goes on the opposite side of the crank arm so the nut is clamped to the arm and the handle can spin freely, but held in place by the head of the M3 screw.