I,m not sure on the diamenter of the auger ,but I Made mine out of threaded rod for my lazer. Just find the rod that fits in your auger and drill a hole for the bolt to go through and then put on 2 nots that hold a flat peice of metel so it does not fall down the hole and the end that goes to the drill make into a triangle to fit.
Works great and is easy .
From Jeff