Keyways in shafts and collars - How to properly cut?

[J S Machine]

I work in a toolroom for a large plant and am often asked by maintenance to make parts for machines. These are commonly shafts with keyways and/or collars/sleeves/gears/etc with keyways.

I have never learned the correct way to measure on how to cut them, and was wondering if you guys knew how to do it right? Is there some sort of standard I "should know"?

I have used a broach before, but we deal with so many different sizes , there may not always be a spacer to go in the bore to do an internal keyway.

Shafts are not usually a problem, becuase they are out in the open and an endmill will easily knock those out.

I have a wire EDM, and in an instance like now where I have a bore that is not common size, I will just burn it. Problem is, I don't know where to measure from to be sure the key way is deep enough.

Does most keystock measure exactly what it is or is it a tad undersize? For example: Is a 1/2" piece of keystock .500" or closer to .495" +/-?


I have included this picture so my question is a little more clear. Each keyway type has two possibilities where measurements could be obtained. Which is correct?

[RICHARD ZASTROW]

J.S. Machine, If you do not have a copy of "Machinery's Handbook", I strongly suggest you get one.

All the information you need and more than you will ever need is in there. In mine, (26th edition). it starts on page 2342.

There are different fits for different applications. Usually its a very tight fit on the width and slight clearance on the height. Page 2353 in my handbook has all the information you are looking for.

Dick Z

[J S Machine]

Originally Posted by RICHARD ZASTROW J.S. Machine, If you do not have a copy of "Machinery's Handbook", I strongly suggest you get one. All the information you need and more than you will ever need is in there. In mine, (26th edition). it starts on page 2342. There are different fits for different applications. Usually its a very tight fit on the width and slight clearance on the height. Page 2353 in my handbook has all the information you are looking for. Dick Z

I do, but I'm not sure what edition I have. I will look there and see. Thanks

[Shane123]

I agree with Dick, its in there. i took mine to the copier and made a cheat sheat of that page because 99% of our business is shafts/gearboxes/conveyer systems, so most everything gets keyed. we dont use slipfit much. wait till you have to play with euro-drives, dunno where they get their keyway dimensions, most of the time we get the motor in and reverse engineer their keyway setup.
Machinery's handbook for machine ... - Google Books

as for making them in collars, you can buy broaches that come with the offset plates, and also you can buy guides, but those are simple to make once you know the dimension you are shooting for. when using a hydraulic press for broaching, i have found its best to go down an inch or 2, back it off to release stress, back on, back off, back on, back off. the reason you would do that is to ensure that your broach is cutting straight and not walking into your part crooked. then go thru it with your offset plate, and then again and again, depending on how many plates you have to offset it.