10-09-24, 11:58 AM
In my experience these sprockets are hardened steel. Incredible forces are transmitted from the splines to the teeth. Cutting this material on a lathe is extremely difficult, welding it will result in cracking. The only proper method what I can think of, is annealing it to reduce hardness, machining/welding it and then heat treating it to proper hardness again. Without knowing the exact alloy it's not gonna be easy... let alone to find a machine shop who will do this for you, and then there's the cost.