[tsaksa]

I have at times cross drilled a shaft starting right in the key-way. A cotter pin then can be used to secure both the gear and the key. But of course this assumes that you have clearance for the cotter pin, and are able to cross drill the shaft, which are sometimes hardened to the point where drilling is extremely difficult. In this case a small diameter carbide tipped concrete drill (one that has never been used even once on concrete) can be effective in drilling some of the hardest materials. But always exercise extreme caution when working with such hard materials.