Cutting a keyway the hard way.

GunsOfNavarone said:
@mikey so instead of a dill bit then clean up with a file, you're saying just use an end mill, leave it round at the top where the keyway meets the pulley's keyway?
You're a moderator around here? I think you need to write an 1500 word essay why we don't do that around here...
;)
Click to expand...

Yes, that's exactly what I'm saying. I've done it like that and had no issues. For a pulley, the key simply resists rotation; the pulley is held to the shaft by one or two set screws. The precise shape of the keyway in the pulley doesn't matter and a keyway with a rounded top will not significantly reduce strength so why not make it easy on yourself? The proper tool is a broach but not all of us have a broach ...
 
That is so me, to short cut it...trying to turn over a new leaf....this week maybe two? Anyway, I don't know if anyone would be proud, but I am in the process of making a broach. Will post pictures, but only because I'm proud of not lazy-butting it on this, unless I screw the pooch, then I was just joking, I really didn't try to make a broach.
 
There are many ways to cut an internal keyway. For steel, I use a broach or take the time to set up the shaper. For aluminium and brass, being softer metals, I have often used two or three hacksaw blades tied together and roughing in the cut. Then finishing with a three square file. Broaches work well, if the keyway is a size I have on hand. I don't have any metrics.

An end mill works quite well most times. Stiffer than a twist drill, it will be less likely to run off center. But for speed when I'm in a hurry, the hacksaw blades do the trick. And are a lot easier to find in the field for a "portable" job. For aluminium, a few wraps of good electrical tape will do the job for holding them together and as a "handle". It won't last long, but long enough.

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So, it will work...but I enjoyed the experience. Just doing aluminum, didn’t know I had an option besides a $500 broaching set. Probably will make this again & try a little harder watching the details. Thanks for the directions guys!
 

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I bought a used broach set last week for $50
 
@Buffalo21 I will give you $60 plus shipping for your set.
Are we talking the sets with the cutting teeth on a long rod and you continually add more shims? That was all I was aware of until someone(s) pointed me to the videos. At any rate, I don't have an arbor big enough for those and my shop press would take days. How this one works? We'll see. I suspect good on aluminum.
 
Here is the set I got

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I don't know what brand that is but..
MSC $350-$450
Broach
Still 2-$300 on Shars, I believe you got yourself a very good deal. Hopefully after these 2 pulleys, I won't need one for some time
 
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