I was able to get through mine w/ a hand drill and a vise. I must have got and relatively soft one. I did drill a pilot hole. The aluminun part is soft, if it won't go through the shaft pretty easily, then stop and take it somewhere.

It ain't got to be pretty, it's hidden..... Just remember to loosen your slipper way up, if you don't your idler gear will most likely be toasted.