Very stuck set screw 3/32

Is the set screw really tight or did the screw head strip because of a poor fitting wrench in a poor quality set screw?

Maybe a tight fitting Torx bit could be tapped with a hammer into the screw socket and liquid super glue added around the bit/screw junction. Don't get any glue on the flycutter body. Let the glue set really well then see what gives.

Yes, it is incredibly tight. I snapped 3-4 allen wrenches before it finally stripped it. When it stripped it was from using vise-grips to hold the wrench and tapping the vise-grips with a hammer. FYI, normally I'm not this abusive to tools. I'm guessing I tapped the hole to too tight of thread engagement and then it shrunk when it was heat treated.
 
Athanasius, Yikes, my bet is you will have to drill it out.
 
Am I mistaken that set screws and socket head cap screws are "automatically" grade 8? I'm pretty new at this. Also, thank you all for the outpouring of advice and tips. I will probably try a combination of perhaps a welded nut and home brew penetrating oil after I try a second attempt at drilling.

I don't have a clue if set screws are supposed to be grade 8 or not. The ones that came on my knock-off QCTP were very soft. Just looking at them funny stripped the head. I was able to find set screws that are grade 8 but it took some doing. The screws are like night and day. I think I would break the allen wrench before the screw head would strip.
 
OP I think your suspicion is correct and the thread galled causing the screw to seize. That most likely being the case I would set it up in the mill square off the broken screw so you can get a good center drill on it. Get a sharp drill bit and go slow it will drill fairly easily. I would drill as much out as possible w/o drilling the existing thread pick out the remaining screw and chase hole with a tap.Good luck
 
Lots of great advise on getting out the screw above, Ive nothing to add to that. I may be wrong but 3/32 hex key would mean a #10 screw. I am hoping its not 10-32; which is IMHO is the worst thread ever for problems and I never use it for anything I can put a 10-24 or larger thread into. They just seem to be the dark child of threads.

Looking forward to see how you get it out.
 
Do you have any high speed tools?

HF has a 60,000 rpm hand piece for reasonable cost.

They also have diamond burs but carbide dental burs on ebay will cut that like cold butter.

A careful hand and you can drill right through the screw and slot it towards a side so it can relax and come out.

Re - tap the holes with a good tap very carefully to insure heat treat did not bugger them up.

Sent from my SAMSUNG-SGH-I337Z using Tapatalk
 
If it makes you feel any better I cut some beautiful 36 TPI thread in aluminum yesterday. Apparently, I got the tolerance too tight. The first time I screwed it together I could not unscrew it. The aluminum must have galled. I used liquid wrench etc. but no movement. Finally I forced it loose with a wrench. When it came apart there were no threads on either the male or female parts. Great.....
Robert
 
Time Sert is much - much better than a Heli-Coil.

A Time Sert is a FULL insert that will now give you steel threads in your Aluminum tool holder.

They are commonly used by Racers who will pro-actively drill out the threads on Aluminum Motor Blocks and replace them with Time Serts.

By doing this they now have Steel Threads in the block and can strip down the motors for maintenance with out worry of stripping out the Aluminum.

More costly than a Heli-Coil but much more permanent.

http://www.timesert.com/
 
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