Cutting Keyways Without A Broach

[Bill Mc]

Hi fellas - Was wondering if you had any tips on cutting keyways without a broaching machine. I figure you can make a keyway slot on a shaft with the milling machine somehow, but how can I put a keyway slot into a five-eighths inch hub hole that is one and three-eighths through? I'm stumped. - Billmc (the NEWBIE)

 

[Jasonb]

Use a boring bar holder with a tool ground to the width of your keyway and "plane" the cut in using the lathe carrage, takes a while at 1-2 thou per stroke.

Did the 4No 3/16 keyways in this gear center 1" deep steel

Jason

 

[tel]

Yep, wot Jason said, BUT it is best to remove the bulk of the metal by drilling. This should be done at an early stage, before the hole for the shaft is done. Mark out your shaft hole centre, now mark the outside of the hole, somewhere on the mark, put a centre pop and drill thru there at key size or marginally under, then go back and do the main hole in the usual way.

If, by some misfortune, you have already done your centre hole, then fill it with a tight fitting plug of the same material and drill through on the junction line.

 

[tel]

Oops, this is for the sewing machine wheel? Go with plan B above. BTW, a with a keyway drilled out like this it's relatively easy to finish it by filing.

 

[putputman]

Bill, Rob Willson had a thread on casting parts and one of the parts he casted was a tool that he used to cut keyways in a lathe. I didn't bookmark the tread and am having trouble finding it. Hopefully Rob will jump in and show you his solution. It is really a neat tool.

 

[Brian Rupnow]

And if all else fails, buy a steel pulley with the bore and keyway you want, turn it down untill you have a hub with a keyway, then bore out the center of your sewing machine flywheel and weld the hub in. -It works.

 

[Bill Mc]

Thanx everyone for the great suggestions. I will employ them in my next build. - BILLMC