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john b
06-15-2010, 11:45 AM
Hi! my name is John and i like tools. Machine shop machinist (job shop) for 15 years and on site machinist for 20+. Did not want to get involved i the p---- contest in tilted key slot, so start new thread. When i was in the shop we cut our key slots to full depth in one pass using a very short 3 flute end mill,cool mist, designed for that operation. Results were very good. Thanks John b.

Dr Stan
06-15-2010, 12:07 PM
Hi! my name is John and i like tools. Machine shop machinist (job shop) for 15 years and on site machinist for 20+. Did not want to get involved i the p---- contest in tilted key slot, so start new thread. When i was in the shop we cut our key slots to full depth in one pass using a very short 3 flute end mill,cool mist, designed for that operation. Results were very good. Thanks John b.

I've also used these cutters usually called keyseat cutters so they should not be confused with end mills. Another option on shafting is to use a Woodruff keyseat cutter and come in from the side. One pass at full depth and you will have a straight on size keyseat.

Mcgyver
06-15-2010, 02:05 PM
welcome to the forum.


Did not want to get involved i the p---- contest in tilted key slot, so start new thread.

both good ideas :D welcome to the forum, just step over the endless parade of P contents.

I've not seen or used the cutter you describe but i'll watch for them, I often use a woodruff cutter...like a horizontal mill cutter, that the force is directed down into the work means the slot always comes out the right width and finish

Black_Moons
06-15-2010, 02:53 PM
Pssst... a woodruff cutter, while made of metal, Like everything, Is actualy made of rubber. Or at least, you should think that way when it comes to cutting with it. Its just unlike a typical endmill, its got much more meat to it, and less flexable cutter. cutting forces will still bend it and likey make it tilt a little in the process since it is only supported from one end, Care must still be taken.

A very stubby (short flutes) endmill would also be much more rigid then a typical endmill. even if it is just an endmill, OP is correct in that a stubby one is best.

Mcgyver
06-15-2010, 03:16 PM
Pssst... a woodruff cutter, while made of metal, Like everything, Is actualy made of rubber. Or at least, you should think that way when it comes to cutting with it. Its just unlike a typical endmill, its got much more meat to it, and less flexable cutter. cutting forces will still bend it and likey make it tilt a little in the process since it is only supported from one end, Care must still be taken.

A very stubby (short flutes) endmill would also be much more rigid then a typical endmill. even if it is just an endmill, OP is correct in that a stubby one is best.

right, but the direction it flexes in is aligned with the shaft vs the lateral movement an endmill flexes in - the endmill flex increases the width of the slot and hurts the finish on the sides. In my experience its a lot easier to get a well finished and dimensioned slot with a woodruff cutter....if your flexing it too much, slow the feed down :)

Carld
06-15-2010, 07:09 PM
I use a two flute endmill to cut keyways and I don't seem to experience the problems some have. I don't cut the keyway in one pass, I usually do it in three passes. I also cut both directions and that balances the side walls as far as I can tell.

A two flute endmill will pull to one side as it advances and when you reverse the cut it cleans up the other side. While that still leaves a slight undercut one one side the other side will be straight.

I have cut a keyway in two passes but I still have not have an issue with it although two flute will cut a slightly over width slot and unless you want to have the keyway so tight you have to drive the key in the slot it's not a problem.

I think a three flute endmill would undercut on both sides so that the slot would be wider at the bottom than at the top. If that is not a problem the use a three flute, just be aware it sucks in on each side rather than one side. Also, the slot may be wider than with a two flute.

I think some make a mountain out of a mole hill when cutting keyways.