Hey folks. I have a 5' bush hog with a shear bolt. The input shaft of the gear box only has a 3/8" hole, not 1/2" like every other one I've seen. I break this shear bolt fairly often, and I'm quite sick of it. Especially since I have a slip clutch as well, so the bolt really isn't necessary. Unfortunately it is not a splined input shaft. So I would like to ream this hole out so I can put in a grade 8 1/2" bolt and hopefully never break it again. Obviously I can't do this with a regular drill bit. What is the best way? Should I use abrasives and a die grinder? Carbide drill bit?