Keith, it is a bit of a mystery so far, and I haven't found anything in the parts list which Deejay found, to clarify it. Can you post some pictures showing an axial view of the end of the shaft, from close-up, and various lateral views of the damaged sprocket in various rotational positions please? Also, your picture shows that the end of the shaft has either been center-drilled, or has an internal thread - can you tell us which it is?
