Charlie
Need to know if the gear can be bored, do the file check and if it's possible and you supply a piece or two of silver steel(extra for F**K up) for the shaft, and 4 pieces of smaller dia silver steel that will fit into the space between the gear teeth i will give it a try. Can't promise it will be a success but will give it my best shot before you have to spend silly money on the professionals.
Mike.
Get the file out