Jointer cutterhead pulley rattle

Hi,
I have a problem with a 8" Grizzly jointer that I got secondhand. The cutterhead pulley is held on the shaft with two set screws and a key. After running the jointer over very light loads for an hour or two the key invariably works its way loose and flies out of the pulley. There's a guard mechanism around it so it just rattles like hell until I can power down the jointer. But this has happened several times.
The first time it happened I replaced the pulley and set screws thinking it was a defect in the pulley itself. This did not fix the problem. I've tried really cranking down on the set screws and leaving them a little loose. No dice, it always happens again. I've also replaced the drive belts.
The alignment between the cutter head pulley and the drive pulley looks fine. Likewise the cutterhead shaft itself seems balanced and, when I've just "fixed" the problem the machine runs quietly with no evidence of vibration. I'm out of ideas about what to do at this point... I almost want to weld the damn key onto the pulley. :(
If anyone has advice I would be very appreciative.
Thx, Scott
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On Tue, 07 Aug 2007 02:23:28 -0000, snipped-for-privacy@gmail.com wrote:

You might check to see if there is excessive wear on the pulley. With the set screw loose check to see if you have any movement in the pulley. Just kinda grab it and twist. If you feel very much slop, you may just need a new pulley.
Mike O.
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Mike O. wrote:

I think he said that he already did that.
To the OP:
Try some fast setting epoxy on the key. Or super glue. It will release with a tap when you want it off.
Also, try a new key. I have key stock that I just cut off new keys when I need one and I have found that the burred edge that is left when I cut one helps to keep it in place.
--
Robert Allison
Rimshot, Inc.
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On Tue, 07 Aug 2007 03:49:45 GMT, Robert Allison
Ooops my mistake.......
Mike O.
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My best guess is the shaft and pulley have a bit of clearance between them, probably the shaft is a bit undersize since you replaced the pulley with no improvement. I would pick up a small tube of red Locktite and apply it to the shaft and reinstall the pulley. Clean both well with lacquer thinner, or brake cleaner first. If you ever need to remove the pulley just apply heat and the Locktite will give up it's grip. Greg
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I agree with the poster who suggested that there may be too much clearance between the pulley and the shaft. If this is true, try to sneak a shim in between Maybe a piece of pop can or thinner if needed. Here's a way to keep the set screws tight: Get really short set screws so you can put tow in each hole. Tighten the bottoms ones real well, then drive the upper ones down onto the bottom ones. This is often done on farm machinery and that's the way they hold the pto clutch onto my Cub Cadets.
The ultimate fix, (if the pulley is loose on the shaft) would be to get a new pulley (again), but one that has an undersize bore. Have a machine shop bore this pulley to be a light push fit onto the shaft.
Pete Stanaitis -----------------------------------------
snipped-for-privacy@gmail.com wrote:

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spaco wrote:

....
Diagnosis of fundamental problem is probably "spot on". May be that as well as the pulley hogged out the shaft is worn. If so, it probably isn't truly round which keeps the pulley from setting tight uniformly around the shaft. Hence, it flexes and that will loosen the set screws.
The locking screw on top of the first is a good tip, for sure.
If there's sufficient gap to get anything as thick as can stock in, there's only a slim chance it's gonna' hold w/o some help in really fixing the problem ime.
Smaller problems may be fixable and one can buy shim stock in various mill thicknesses.
--
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Get a steel sheave which can handle the vibration set up by the intermittant cuts of a jointer.
BTDT.
Lew
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