I got a screw loose...

Tom Hempleman

Member
Messages
9
Location
Carroll, Ohio
I hope someone has a solution for this problem. I have a relatively new Delta benchtop belt/disk sander. The problem is that the disk plate won't stay tight on the shaft. The little set screw that holds it on the shaft comes loose after a few minutes of use no matter how tight I can get it with an allen wrench. If it weren't for the dust guard around the disk, the thing would probably fall off and go skating across the garage floor. I've replaced the set screw twice thinking that would fix the problem but no luck. I suppose I could put a drop of Loctite on it but then I would never get the screw loose if needed. Anybody got any suggestions? :dunno:
 
You are talking about the disc part of the sander, that goes onto a motor shaft of some kind? Does it just slide on, or does it screw on to the motor shaft?

You could drill and tap a second set screw hole, like Tod suggests, an or you could change the set screw, what kind is it, is it flat on the bottom or pointed? A pointed set screw might grab better on the motor shaft, and once you get it positioned just right, crank down on the set screw, then take it off, and you will have a small mark on the motor shaft, you could then drill a VERY shallow hole, like 1/32" deep, for the set screw to hold into.

Loctite is your friend, in this case, I's use the blue stuff, NOT the red, the red is really, really hard to get loose again, usually requiring a heat gun or such.

Good luck, I'm sure you can cure this problem.

Cheers!
 
bill`s correct,
S.O.P. on lotsa vibration prone pulleys ect. is to run another set screw down on top of the first to lock it in place.
 
Depends, if the hole has some room and there is sufficient clearance then just putting another on top with a slight protrusion will work.

I first saw this in 1963 from an old timer in the Western Union labs. Someone need a quick fix on a set screw on a machine while making a prototype and the lab foreman was asked by the engineer to get it fixed in a hurry. He added the second allen screw and left. We just stood there dumbfounded.
 
There are different kinds of Loctite. I have used red for decades on gun parts. With right screwdriver, it can be removed again. But check info on packages. Another solution might just be to mess up the threads on the screw. Make them rough with another tool, that often prevents loosening. Learned that from a race car mechanic.
 
Many posters are correct about Locktite.

Here is another trick.
Take a prick punch and peen the top edge of the screw hole just enough to put a drag on the screw, a trick used 100 times in the machine shop.
 
I'm with most of you guys....


We often run two sets screws on a pulley or sprocket on a motor shaft. One short screw tightens to the shaft. A second short set screw in on top of the first to prevent the first from backing out.


We also use blue loctite 242 IIRC......and on occasion we use red loctite....We even occasionaly use a special loctite that made for use in hydraulics....
 
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