[Matt Reiland]

You can put an internal keyway into something thru- bore without a broach using a milling machine and an endmil that has a diameter the same width as the keyway. Plunge in the endmill in the same direction as the keyway into the material. At this point you can make this new U shaped keyway deeper than what is required to accept the key or you can file out the round edges with a hand file to get back to square. We did it this year into sprockets and they were literally identical to the broached keyways with a little bit of effort.