Cutting Keyways

[GeneT45]

For a one-off it's probably best to mill a (round bottom) slot and file out the rest - a little labor intensive, but not prohibitively.

Here's a tool I used to broach a gear. The major diameter is the diameter of the bore, so deflection was not an issue. There is is set-screw through the shaft under the the HSS cutter to push it out as the cut progresses. I used the carriage to push it, it was hard work. Probably would have been better with the tailstock.

I've since bought a set of broaches and 3-ton arbor press, haven't needed them since.

I like that. Get rid of the hose clamp and it's pretty much a rifling cutter.

GsT

 

[deekaybell]

the hand wheel I was making wasin aluminium and had a 10mm (0.393") central bore. it needed a 3mm (1/8) keyway. I used an 8mm boring bar with a small piece of 3mm square hss tool steel normal to the bar. I found that I could not get the grub screw tight enough to stop the tool steel from sliding back from the work surface into the boring bar. I had to continually reposition the tool steel. I didn't actually tie the job but I think it took in the order 4 hours to make this one keyway. This is why I was looking for a more robust method of cutting keywards

Thanks for the suggestions everyone