Set screw disaster (stuck)

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Robert757

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Apr 23, 2013
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I have a set screw that is stuck deep in a 6 inch aluminum drive wheel. It is a solid drive wheel so the set screw is an inch and a half down in the hole (at the bottom). The hole is too small and too deep to get an extractor into. I’ve been trying to drill through it with a long bit so I can drive something into it but I’ve hit a hard spot and the bits are just rounding over. No carbide bits that long in my area.
I was thinking to just give up on it and drill/tap a new hole but the set screw is actually sticking down a bit into the keyway, and would interfere with the shaft, so that is out.
I’m seriously considering finding an acid that will eat the steel but not the aluminum.

Any ideas and pity will be appreciated
Thanks
Robert
 
This sounds like the type of nightmare that would happen to me. I wish you the best of luck. I wish I had some advice for you, but it sounds like a disaster.
 
Maybe you could carefully grind off the protruding end of the set screw with a Dremel? I doubt scratches inside the journal right around the screw would hurt anything, as long as you didn't let it slip on ya too far & totally made the bore egg shaped.
 
Thanks Viral. Im finding alot of references to using alum from the grocery store spice area, disolved in water and slightly warmed. Its worth a try and alot safer that bottle of muriatic acid that is calling me.
Ill see what happens overnight.
 
Robert757 said:
I have a set screw that is stuck deep in a 6 inch aluminum drive wheel. It is a solid drive wheel so the set screw is an inch and a half down in the hole (at the bottom). The hole is too small and too deep to get an extractor into. I’ve been trying to drill through it with a long bit so I can drive something into it but I’ve hit a hard spot and the bits are just rounding over. No carbide bits that long in my area.
I was thinking to just give up on it and drill/tap a new hole but the set screw is actually sticking down a bit into the keyway, and would interfere with the shaft, so that is out.
I’m seriously considering finding an acid that will eat the steel but not the aluminum.

Any ideas and pity will be appreciated
Thanks
Robert
Click to expand...

Why is it stuck, waas it loc tited ?

It needs propane tourch heat. six or seven hundred degrees

Set screws are also pretty hard.
Sharpen your drill bits, or get new ones.

Propane torch heat the set screw red hot and let it cool slowly
It may be difficult with all the aluminum heat sink, but it will soften the screw and help do drill it.

If you use a left hand cutting drill, it may catch and screw it self out.



Be for y ou started rilling, I'd have given it heat to kil the loctite
 
Did you try using a torx head bit before you started drilling it out? I have almost always been able to get out damaged hex drive fasteners by tapping a tight fitting Torx into the socket.

Bob
 
Maybe you could drill out the hole a couple sizes larger. The combination of an increased inside diameter and a larger bit may keep the bit from slipping off the set screw, and instead, drill through. Of course, you'd have to re-tap the hole and get a larger set screw.
 
if worse comes to worse, you can drill a hole 180 degrees and grind some off the height of your key. you will probably need a pulley tap to thread the new hole. if you end up doing this you will want to file a flat on the shaft where the set screw contacts or you'll have a hard time ever removing the wheel again.
 
I think at this point, I'd personally just punch it through to the other side and drill and tap the hole a size or two larger.
 
First, take some nut-buster or similar penetrating oil, heat the screw, and run the oil down the hole. Next, take a torx bit that is a size larger than the Allen wrench. Taper the end a tiny bit. Tap into the set screw while turn it INWARD. Screw right out the center hole. you can apply more heat as needed while breaking it loose.
 
A shaft key, would have stopped that set screw from going into the keyway.
 
Thanks for all the great ideas. I had tried the torx thing for a while before work this morning but I was really worried about heating the aluminum too much because the the set screw is so buried in it, at the bottom of the hole and pretty much centered in the 2 1/4 inch wide wheel. almost impossible to get the tip of the flame on it.
right now its in the Alum bath in an old crock pot and bubbles are coming out of the set screw hole, so there is promise.
If that doesn't work by the time I get in from work tomorrow I'm going to start on some of the other methods you have provided.
Thanks so much!
Robert hatcher

PS, there was no lock-tight in the hole. this setup is barely a year old. I don't know what happended.
 
I make a long left hand drill with a dowel pin ground into a spade and sharpened the same way you'd grind a right hand drill but mirror. You drill in straight a ways and then encourage it to bind by tweaking the angle a bit. This almost always unscrews a stuck setscrew.

If it's in aluminum you can heat the work which makes it expand quite a bit and will loosen most any stuck screw.
 
Lieblad speaks the gospel on the anti-seize. While it won't fix your current problem, it will help prevent your next one.
 
A left handed drill bit from Grainger or Mcmaster Carr works almost
every time. Just run your drill in reverse and keep the speed kind of low. The reversed flutes will often back the screw out. I have removed hardened steel bolts from aluminum and magnesium using them.
 
I had a call to free a large cutterhead on a commercial wood working machine,that had seized and galled to the shaft .They said HELP ! no screws involved just seized many hours later I finally freed the cutterhead !!!
I never had much success annealing screws .I wonder if hand turning would be better --after filling the hole with penetrant and waiting. You might have to make a tool to fit the screw .Have fun !
 
Well, after 16 hours in the hot Alum bath I was able to force a Torx driver in and turn the set screw into the shaft hole. I tried a few times during the process but this time the screw was spotless and came out easily. the screw hole had been steadily bubbling with black bits coming out most of the time. It could have just been the prolonged heat but I suspect the reaction of the steel and the alum cleaned the guck form around the threads.
Thanks again for the brainstorming!
Robert
 
I wanted to follow up in case anyone wanted to try this. As it turns out, the process did take a little off the surface of the aluminum. Overall the surface had a pickled appearance which was not a problem but there were two issues. The setscrew hole threads are oversize (loose fit) except where the original setscrew was located. It is impossible to thread the screw down from the top but I was able to thread it in from the shaft hold with a but of finagling and it locks solid. The motor shaft fit slightly loose backing up my suspicion that the aluminum was attacked in the process. I overcame that by abrading the shaft hole with a sharp piece of steel (like a graver) and working it on and off the shaft a few times. In all, I survived it but if I had to do it again I would try one of the other methods shared here before I resorted to this again.
Robert
 
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