Sprocket Mounting Hub (Removable)

This describes the design and fabricated of a sprocket hub with the primary advantage of easy attachment and axial adjustment on 1.5″ OD wheel rim hubs. Materials used consist of 1.5″ ID, 1/8″ wall steel tubing (DOM) for the hub collars, 2 hub collar set screws securing it to the wheel rim hub and 3/16″ thick 2″ steel squares used for the sprocket hub plates each with 4 threaded screw holes to mount the sprocket. Fabrication operations include

1. Drilling/tapping set screw holes through perpendicular planes in the steel tubing sides
2. Lathe parting 1″ long collars from the steel tubing stock ensuring their ends were square, required for the hub plate welding
3. Cutting 2″ squares from the 3/16″ thick, 2″ wide rectangular bar stock
4. Clamping and welding the steel squares perpendicularly to the ends of the hub collars.
5. Lathe facing a 1/16″ boss registration feature matching the sprocket ID to ensure concentricity of the sprocket and collar.
6. Boring the inside of the hub collar to achieve a good fit to the wheel rim hub.
7. CNC/manual mill drilling/tapping 4 sprocket mounting screw holes at the corners of the squares.

Here are images of the sprocket hub and assemblies with the 10″ pneumatic tire wheel and 55 tooth #25 chain sprocket.