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

[Pmedic828]

Does anyone know how to cut a key slot in a shaft without using an end mill? Watched various youtube videos watching machinists work and on more than 3 sites, the machinists said not to cut a key slot in a shaft with an end mill because the end mill would either chip because it is hitting 2 sides at the same time, or it will wonder and not produce a straight slot. They, however, didn't explain how to do it with magic? Can anyone enlighten me?

 

[JR49]

the end mill would either chip because it is hitting 2 sides at the same time, or it will wonder and not produce a straight slot.

You can use an end mill that is smaller than the width of your key slot, then trim each side separately to bring the slot out to proper dimension. Good luck, JR49

 

[T Bredehoft]

If you can figure out how to hold the shaft, you can do it with a woodruff cutter.

Last week I used JR's method. 5/64 two flute to make a 3!6 keyway. And where did I get a 5/64 2 flute cutter, I bought about 50 of them on Ebay for $16.00, free shipping.

 

[joshua43214]

The mill should not chip just because it is hitting two sides. Milling a slot is after all one of the things mills do...

JR49 and Tom nailed it, either plow the groove and widen, or use a key cutter
http://www.use-enco.com/CGI/INPDFF?PMPAGE=115&PARTPG=INLMK3&PMITEM=367-2100

Key cutters are regarded as being better because they add less of a stress riser, but plenty of shafts are keyed with a mill.

 

[JimDawson]

I've keyed a lot of shafts with end mills, in fact that the only way I have ever done it. Never had one chip. But you want to use a sharp 2-flute. A 4-flute will pull sideways and make the keyway oversize. Or as said above, use a smaller cutter and step over.

 

[Bill C.]

Does anyone know how to cut a key slot in a shaft without using an end mill? Watched various youtube videos watching machinists work and on more than 3 sites, the machinists said not to cut a key slot in a shaft with an end mill because the end mill would either chip because it is hitting 2 sides at the same time, or it will wonder and not produce a straight slot. They, however, didn't explain how to do it with magic? Can anyone enlighten me?

I never heard that one before. If you use a milling machine be sure to tighten the cross feed clamps. Helps to snug the table feed clamps so the cutter doesn't pull itself. I have used to many used milling machines.
Now the old school method, early 1900's, those machinist would drill a series of on size holes drilled to the requires depth leaving material between each hole. Then using a flat chisel and ball-pein hammer cut out the remaining material. Then they would use a flat smooth file to cleanup the slot. If you ever tear down a old drive shaft and see a series of drill bits hole that how they cut their slots.

 

[kingmt01]

If you ever tear down a old drive shaft and see a series of drill bits hole that how they cut their slots.

I've seen this a few times.

 

[Whyemier]

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.)

 

[jeff_g1137]

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.)

It was a long keyway LOL

 

[Ulma Doctor]

i have used small diameter slot cutters on the horizontal mills to success ,
woodruff key cutters & 2 & 4 flute endmills on the vertical mills,
use an endmill smaller than required for final dimension,
make multiple passes to creep up onto dimension if you are unsure.
it's easier to remove metal than it is to put it back!
good luck