How To Cut A Key Slot In A Shaft Without End Mill

[juiceclone]

We usta, that was in the dark ages, chuck the shaft, tube, bearing, whatever, up in the lathe and drag an appropriately sized tool bit, set up in a boring bar, tediously centered, down the inside of a tube or the outside of a shaft to cut the keyway. Got a lot of spring in the bar but it worked after a fashion. (Hmmmm? That was a long sentence. Guess my grammer etc. ain't that good.)

Yes..been there, done that. tedious, but if it's just one keyslot, what the heck, it'll get er done. :>))

 

[royesses]

According to the metallurgists who taught our classes the radius must be smooth with no steps. There is still increased stress due to the notch. I don't recall any formula given for the radius dimension. Even striations that you can feel with a fingernail act as a stress raiser. Polishing to a mirror finish also reduces stress raisers. Many mechanics radius and polish the base of gear teeth on differential gears to help prevent failure, mainly on circle track cars.

 

[MUSKRAT]

This is my first post, saw this and thought I would share this picture of shaft failure due to the sharp edge key way. the break always starts at the edge. thanks for all your post.

 

[bfd]

an endmill is supposed to cut slots if it chips get another end mill to finish up the slot. taking light depth of cuts will help to ease this from happening. cutting keyways with an endmill is the only way I have done it on shafts might have broken an and mill or two. oh well. bill