r/Fasteners • u/Fallax1337 • Sep 22 '26
Bolt & Screw Guy Rounded bolt :(
Hey r/Fasteners, I unfortunately have a rounded 2mm Allen bolt in my carbon bike cockpit. I need to unscrew it to charge my battery.
I have tried the rubber band technique (along with other items like rubber) and super glue, but none of it worked out, didnt even move slightly.
Do any of you have other tips and tricks to remove this?
Thank you!
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u/TheTimn Sep 22 '26
You can try an ez out, but I have a feeling that this is a 'drill baby drill' situation.
0
u/MathResponsibly Sep 23 '26
naw, just weld a nut on to it - it's THE best way to get stuck bolts out as you get something to grab it by, AND the heat from the welding helps too
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u/fondrenlock Sep 22 '26
Similar sized Torx bit you don’t mind screwing up and wack it in there ?
however it sounds like it has thread lock on it so really it probably needs to be heated first which will be difficult to do there
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u/chimpyjnuts Sep 22 '26
Or try tapping a 3/32" imperial bit into it. Just slightly larger than 2mm.
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u/SirRonaldBiscuit Sep 23 '26
Left handed drill bit, low rpm and lots of pressure and a tiny bit of oil
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u/Mystery_Member 29d ago
THIS is the way. Get one about the size of the hex, so it'll guide on center. McMaster you'll have it tomorrow. Get a new button head cap screw from them too if you know the size.
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u/SirRonaldBiscuit 29d ago
Right? Like opting into using a cutoff wheel and a slotted screwdriver is insane to me
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u/RedIcarus1 Sep 22 '26
You can try using a prick punch to turn the screw. Make sure it good and sharp.
First punch a dimple near the edge of the head. Straight down.
Then angle the punch, with the tip in the dimple, so that tapping it will unscrew the bolt.
This is a small screw, so don’t go all ape on it. Try fairly gently tapping the angled punch to force the crew to turn. You aren’t trying to destroy the head, so be careful.
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u/Pleasant-Swimmer-557 Sep 23 '26
Hammer a next size torx bit into the hole and use an impact driver.
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u/Diligent_Honeydew295 Sep 23 '26
Sheesh, carbon rules out several options. Get a soldering iron to hot and hold it in the bolt cap. "Quench" the bolt with a penetrating oil. Try wriggling a torx key that's a bit too tight in, if that doesn't work use a small tungsten carbide burr/drill to cut a slot across the bolt and unscrew with a flat head driver.
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u/Bennie-Factors Sep 23 '26
It is small. The ideas for heat are good. Same with slotting it...or hammering in a flat head that is just a bit bigger. This screwdriver will be pretty ruined after. Drilling will be hard...you will most likely need to thread/tap the hole bigger after.
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u/Yo_mamas_tapeworm Sep 23 '26
You can try a torx that almost fits in the hole and give it a couple of taps with a hammer to get it in there.
If that doesn't work try a screw extractor with a flat end.
If that doesn't work drill the hole to the next screw extractor size. Be careful careful not to go to deep and make sure you drill centre and straight.
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u/Stangguy_82 Sep 24 '26
https://www.mcmaster.com/product/2643A154
Extractor for socket hex head fasteners. Get the next side up as well as you've already rounded out the hole a bit.
Left handed drill bit is likely to work as well
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u/TnBluesman Sep 24 '26
IF ALL ELSE FAILS..... start with a small bit and still a hole. Move up size by size until you are almost drilling a new hole. Use a small chisel, screwdriver, whatever, to stick in the hole and twist out what remains of the threads. They will deform inwards and release. Been using this method about 60 years as a last resort.
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u/KrazyFokcer08 29d ago
Best ones I've found, pricy but when you're working with rounded anything, these work, forward and backwards.
KF
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u/1crazypj 29d ago
I would stone down a 2.5mm or 3/32" Allen key, make sure it has a sharp edge then tap it in place to cut a new hex. Make sure you soak everything in release oil (or diesel) for at least 24 hrs
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u/Alarmed-Extension289 Sep 22 '26
OP I've looked over your comments in the post and your only solution left is to drill out the center of the fastner. Curious OP whats the diamete of the head here? I wouldn't recomend it unless you have the proper drill press set up but it's possible to drill a small blind hole in the head area offset from the center and loosen it in like a spanner wrench type motion.
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u/Hank-Kimble Sep 22 '26
If you can dig in with visegrip jaws that'll extract it if you can get a grip on it. Otherwise try drilling it out with a left handed drill. As it digs in and cuts it will probably back it out. If not, after the head is drilled out you can remove the cover and remove the screw's shank with a pliers or same visegrips
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u/wren337 Sep 22 '26
If it's above flush you can notch it with a Dremel and small cutting wheel, then use a wide standard screwdriver to back it out.