[dlavery]

Originally Posted by sanddrag

I'm guessing you'd have to grind a tool that is recangular in shape that is the thickness of the keyway you want. They you'd grind it sharp on the edge (sorry, I'm not describing this well). Think something like a lathe groove cutting tool. Then, I'd rig up something to put it in the spindle of a mill, align it to be parallel with a mill axis (lets say x), and lock the spindle with the brake and/or a very low gear. Then, with my gear already positined in a vice or whatever such that the ground cutter is directly over the gear diameter that is parallel with the x axis, I would make sure the y axis is locked in place. Then, I would proceed to move the cutter into the gear just a little bit, and pull down on the downfeed handle. Move the gear into the cutter a little more, and pull down once more. Each time, you "shave" off a little bit until you get the depth you want.

Close enough. That method will definitely work. Take the same idea, turn it sideways, and you can see how you would do it on a lathe (this is actually the preferred option - with the cutter mounted on the cross-slide - just because there is one less degree of freedom to worry about). Turn it sideways the other way, and you can do the same thing on a shaper. I have also seen it done "by hand" with a one-shot cutter and an arbor press. Drill out the majority of the keyway (as if preparing for a Dutchman Pin), then use the cutter to clean up the corners.

-dave