Very stuck set screw 3/32

Athanasius

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Summary: Very new machinist student gets 3/32 set screw very stuck in apparently poorly tapped hole in R8 fly cutter project.

Now, I'll give you the long winded version with steps I've taken in CAPS.

Hopefully I've uploaded the photo correctly and it is adequate. My steel rule is at school and my teeth held the flashlight for the photo.

I simply hand tightened this set screw tightly until it stopped turning. After that, I've torqued several Allen wrench wrenches both gently and with shock. -and snapped them off. THE ALLEN SOCKET IS STRIPPED.


I've soaked it in LIQUID WRENCH for minutes (and attempted turning it before it was stripped) as well as days. I'm guessing that straight penetrating oil would have been better, but I couldn't find any at the stores I looked at.
IMG_20170115_014653639_HDR.jpg

My father-in-law and I tried the steps for an EASY OUT, but I warned him that set screws were grade 8 hardware. Obviously run of the mill drilling didn't work.

The R8 fly cutter body is case hardened 4140 steel. Though I know it is extremely inadvisable, I even tried TORCHING IT.

Thank you for your consideration
 
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Drill it out. A grade 8 fastener isnt all that hard. The stripped socket will help centre the drill nicely. Just a fraction or 2 under tapping size. If you havent gone into the threads, then go up 1 size. Once you have all but cleared the Minor dia then run new tap through the hole.

Cheers Phil
 
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.
 
I would thread a nut on like Mikey said and then give it a quick plug weld with a mig welder. Then unscrew it.
Cheers
Martin
 
Hello @Athanasius,

Try the least destructive ideas first, then move up the scale.
It looks like you have a bunch of great advice above. Keep chasing it you will get there.

So I'll just add:
Welcome to the site!

-brino
 
I don't have anything of value to add on getting the screw out. Other posters seem to have the subject covered, I would try drilling it out just because of the tight location for welding a nut on top. Just to help with future needs to get a stuck screw/bolt out there are a number of home-brew penetrating oils that work as well or better then some of the store bought products. ATF (automatic transmission fluid) and acetone seems to work for a lot of people.
The results of a "study" are as follows (found here http://www.gmcmhphotos.com/photos/random-photos/p40657-penetrating-oil-test.html)


"PENETRATING OIL - AVERAGE LOAD

None - 516 pounds
WD-40 - 238 pounds
PB B’laster - 214 pounds
Liquid Wrench - 127 pounds
Kano Kroil - 106 pounds
ATF / Acetone Mix - 53 pounds

The test showed that anything, even WD-40, was better than dry-wrenching. But the winner, by a considerable margin, was the home-made mix consisting of 50% automatic transmission fluid, and 50% acetone. This 1:1 ratio allows the thin acetone to carry lubricant deep into the threads of your target bolt.

The ingredients are easy to come by. Acetone can be found among paint stripping chemicals at your favorite hardware store, or you can find it in nail polish remover."

Good luck, quick question, did you replace the set screws with Grade 8 ones?

Mike
 
just out of desperation,
i'd consider using a torx bit slightly larger than the hex socket and pound the torx bit into the set screw firmly.
rather than backing the screw out, tighten the screw inward and remove it from the inside of the flycutter head.
most likely the business end of your set screw is expanded and hanging up on the threads as you are extracting the set screw

another suggestion is to put the flycutter in an oven at 200-250*f for a bit, and then try to remove the set screw and see if thermal expansion is your friend
 
I don't have anything of value to add on getting the screw out. Other posters seem to have the subject covered, I would try drilling it out just because of the tight location for welding a nut on top. Just to help with future needs to get a stuck screw/bolt out there are a number of home-brew penetrating oils that work as well or better then some of the store bought products. ATF (automatic transmission fluid) and acetone seems to work for a lot of people.
The results of a "study" are as follows (found here http://www.gmcmhphotos.com/photos/random-photos/p40657-penetrating-oil-test.html)


"PENETRATING OIL - AVERAGE LOAD

None - 516 pounds
WD-40 - 238 pounds
PB B’laster - 214 pounds
Liquid Wrench - 127 pounds
Kano Kroil - 106 pounds
ATF / Acetone Mix - 53 pounds

The test showed that anything, even WD-40, was better than dry-wrenching. But the winner, by a considerable margin, was the home-made mix consisting of 50% automatic transmission fluid, and 50% acetone. This 1:1 ratio allows the thin acetone to carry lubricant deep into the threads of your target bolt.

The ingredients are easy to come by. Acetone can be found among paint stripping chemicals at your favorite hardware store, or you can find it in nail polish remover."

Good luck, quick question, did you replace the set screws with Grade 8 ones?


Mike
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.
 
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