View Full Version : Keys and Slots

04-27-2003, 06:58 PM
I am taking some one inch stock, threading it and cutting a key slot. This is a first for me. Anyone have any suggestions on how to do this and in what order.

Should I mill the slot first, then thread the stock?

What should the the key be made from?


04-27-2003, 07:13 PM
Thread the stock first, then keyway it...When you single point any threads, you do NOT want an interrupting cut, it will kill your threading tool...especially for carbide, but HSS will take more of a beating...

The only trick is to deburr your slot properly so your threads will still work


04-27-2003, 07:14 PM
what Brent said.

04-27-2003, 10:46 PM
Its worse than they said. If you thread over the keyway, you will probably get bad threads.
This can be due to the tool springing ahead when the pressure is off when it hits the slot.

It is so easy to deburr the cut thread ends that there isn't any reason to fool with it. Run a nut over them, then a thin file down the keyway. If you have one with edge and one side safe, so much the better.

04-28-2003, 10:55 AM
What should I make the key out off, O-1 or or anything I can harden in the shop.


L Webb
04-28-2003, 11:45 AM
Even though I have tons of tool steel in the shop, I still like to use purchased stock available keyway stock.
I hate running into bastard sized things when repairing something.

04-28-2003, 03:03 PM
What depth should I use for the keyway slot? The key width of the cutters is .249", this is being placed on a 1" arbor.


04-28-2003, 03:13 PM
Check in your machinist handbook for the "correct" depth. This is for the same reason that you use key stock.

04-28-2003, 03:51 PM
I found out that it's about 1/8", soft steel for the key.


04-28-2003, 06:45 PM
IMO, the slot should be cut first. It's a whole lot easier cleaning debris out of the slot than cleaning threads.

The cutter will not have a problem crossing the key slot. Been there, done that.

A properly mounted threading holder will not flex.

04-29-2003, 12:11 AM
in general, yeah.

On worn machines?

Maybe, maybe not so sure....slop in the halfnuts, wear on the carriage, etc can easily lead to "lead" errors when pressure is released and loosenesses "unwind" a bit....

This is stuff which would not be of concern if the pressure is always in one direction, and probably is worse at medium-fine pitches, where there is significant cutting pressure, but also a relatively small lead.

Anyhow, I have seen it happen. Screwed up the pitch, but wasn't really too visible. Made the nut sort of self-locking.

[This message has been edited by Oso (edited 04-29-2003).]

04-29-2003, 12:30 AM
The machinery is new, all of the materials are also new, I orered new dies for this project from KBC. I plan on reducing the nuts in my lathe, that is why I ordered the 5 inch chuck from Enco. I can mill the slot with no trouble, I have both HSS and Carbide end mills for such things.

Les has volunteered some keyway steel if he has the right size.

I can try either threading first then cut the keyway or cut the keyway and then thread it. I have a couple of extrea arbors to experiment on if I have to.

Many thanks to all,