Surge Alamo 30 driven pulley keeps coming loose

[Clinkis]

I finally got my vacuum pump and released plumbed in and have been running some tests. Everything is working great but the driven pulley keeps coming loose on the pump. It's the factory original pulley and it only has one locking screw. I've tightened it 2-3 times already and even put loktight on it but it keeps coming loose after 10-15 mins of running. Any ideas on how to keep it tight?

[psparr]

Not sure how long you let the locktite set, but it should set at least a few hrs. better yet 24.

[BAP]

Does the pulley fit on the shaft tightly or is it worn with a loose fit? Does the pump run smooth and is the shaft straight?

[Clinkis]

Shaft and pulley are in good shape and pulley fits snug on shaft. Pump runs nice and smooth. The set screw gets loose and the pulley starts working off shaft. Let loktight sit overnight before I tried it. Wondering if I should be grinding a point on set screw.

[Robert K]

You could use Red lock-tight. You will need heat if you have to get it off again.

[BAP]

Is the pulley on the motor and the pump lined up straight so that the belt runs true? Something must be causing it to loosen up. If everything is right you shouldn't have to use loktite on the set screw.

[Clinkis]

Is the pulley on the motor and the pump lined up straight so that the belt runs true? Something must be causing it to loosen up. If everything is right you shouldn't have to use loktite on the set screw.

I was kinda wondering the same thing about alignment. It looks good. I did adjust it a bit more today but didn't seem to help. I might try replacing the keyway and set screw. Wondering if the're worn a bit.

[mellondome]

Put a straight edge across the faces of the 2 pulleys to verify they are true with each other.

[Ontario Ian]

If you take a drill bit just smaller than the thread, and drill down through the pulley into the key about 1/8", this will give a good seat for the set screw. if the pulley is deep enough you can send a second set screw in behind the first to jam it. you could always drill and tap a second hole 90 degrees from the other one and add another set screw. it doesn't take much wear to only get the one set screw loose.

[maple flats]

When you test the pulley alignment with a straight edge, turn the pulley and retest, do this 3-4 times, you might have a bent spot on one. However, if the driven pulley is the original, it's cast and while still possible, not likely to get bent. I would pull it off and add another set screw at 90 degrees from the keyway. Then tighten both and use new set screws on both.

[Clinkis]

Ok thanks for the suggestions. Will give it another go tonight and see what I can do.

[johnallin]

On some of my older woodworking machines I have switched over to Link Belts. Not only are they adjustable (and handy for an emergency belt) but they eliminate most, if not all, vibration due to misalignment.
They cost more than a standard belt, but I think it's money well spent. Link (no pun intended) is below.

http://https://www.zoro.com/b/POWERTWIST+PLUS/ (https://www.zoro.com/b/POWERTWIST+PLUS/)