• The wheel and nylon gear need to be fixed together. This can be achieved through several ways but for strength and ease of disassembly, (in case it needs to be replaced) we recommend bolting it to the wheel.

• To avoid distortion when bolting the gear to the wheel, we provide a spacer piece. The spacer also acts as a template for drilling three 5mm holes through the gear. You may need to slightly file the the leading edge of the centre hole but it should fit pretty snuggly in to the recess of the gear for drilling.

• 4 of the 4" wheels should be supplied with centering points for the gear bolts.

• Drill 3 no. holes on 4 of the wheels to take a 5mm tap (4.2mm). Drill straight through the wheel. If you are confident at tapping threads then you may not want to drill straight through the wheel but for most of us it is easier to tap a thread in an open hole. The hole in the outer face of the wheel can be filled later before painting.

• Using a 5mm tap bit thread the three holes in the wheel.

Left- mould mark on the Delrin wheel. This face goes towards the wheel/spacer. Use a chisel or knife to remove the raised mark. Put the  gear in a vice and cut the collar off using a large hacksaw, so it is flush with the face of the gears.