Making an internal keyway without a broach?

PHPaul

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Can it be done? I suspect not, but I figured if anyone knew a way, they'd be here. :)

I need to make a spacer to go between two pulleys on a 1" shaft with a 1/4 key.
 
If it's only a spacer , why do you need to key it ? Drill a hole in it so it slips over the key .
 
Ah. I should've known Mr. Pete would have the answer. I think I can make that work.

@mmcmdl - I'm not comfortable with oversizing the bore to accommodate the key as it's on a motor shaft that will be spinning @ 3600 RPM and don't want it wobbling.

I might use a combination of approaches: drill a 3/16ths hole off-center in the keyway posistion and then bore the main hole on center. That would take a lot of the work out of broaching (scraping?) the final keyway.

drillway.jpg
 
Drill the hole off center to clear the key . Keep your bore at 1" . ;)
 
You know they also sell lock collars that are keyed . Machine it to your spacer length .
 
You know they also sell lock collars that are keyed . Machine it to your spacer length .

Looked at those. I need about 1-1/2 inches of spacer, that'd get a little spendy for this tightwad...
 
You know they also sell lock collars that are keyed . Machine it to your spacer length .

Or a locking collar (not keyed) with setscrew.

I like the suggested idea of drilling a hole to clear the key. Your spacer can’t “wobble” if it is sandwiched between the pulleys and it has a correct bore.


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Assuming you have a lathe, Mr Pete covers this in one of his videos.


Cheers,... Jon.

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I agree with Jon, I've done this many times. Take small bites and it turns out great.

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A little sideways input, if I may. I often use a shaper to cut internal keyways. When I'm serious about a pulley et al. In most cases, I use a couple or three hacksaw blades strapped together to make the basic cut. And a three square file to finish dressing it. There are hacksaw blades that will enter a 1/4 inch hole. And files that will work 1/8 inch keyways. Crude, but cheap. And usually faster than setting up the shaper. Usually, the shaper only comes into play when I'm doing something for someone else. The above suggestion is basicly using the lathe carriage as a shaper, albeit a little slower.
 
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