Stuck broken bolt - advice?
 

Although I should've known better, I went and snapped a bolt head removing a fender stay screw during fender fitting. I should've run the tap through it first, alas I did not and it was pretty tight and of course I decided to use my limited muscle instead of my limited brainpower.

Any ideas on getting this out? Just tried freeze-off penetrant and pliers/vice grips, as I expected I couldn't really get a grip on the end. I was thinking of filing a slot for a screwdriver attempt, a stripped screw kit where you kind of drill into it (can do one or the other, but not both), instead of a slot filing flats on the sides for pliers to grip, or if that all fails just drilling it out and resigning myself to nut and bolt on this side.

https://cimg0.ibsrv.net/gimg/bikefor...14059a78e6.jpg

Looks like you still have a good amount of threads left . Why won't that ever happen to me ? Soake it with your favorite penetrant lube and let it sit for at least a day . I recently bought some Kroil , that stuff is good . Liquid Wrench is good too . After a good soaking , the methods you describe sound good . Also if you can make a setup in a drillpress and then use an Easy-Out that could work . Or just drill it out and re tap . If all fails , there are places that do what they call tap burning . I don't think you will have to resort to the latter . You got this !

Being lazy. I'd look long and hard at that bolt and my best, cleanest edged and sharpest toothed vise grips. If I went for it, it's a one shot deal. Side of grips against the dropout, a hard, bolt mashing squeeze, then turn. Might start by center-punching the bolt. After the visegrips, that might be difficult but pre-punched, you might be able to start a drill for an easy-out if the vise grips fail.

Edit: I see you've tried visegrips but not as aggressively as my approach. I'd squeeze until the teeth are beyond the threads and into the bolt shank. Ie, nothing subtle! And this calls for good vice grips. If yours aren't , don't.

Do you have an easy-out?
Otherwise I'm with 79pmooney

Might be easiest to file flats on two sides of that stub and then try with vise grips or an adjustable wrench or put the flats in your bench vise and turn the frame—all after a 24-hour soak in penetrating fluid.

If you can find dry ice, apply then try to remove. Apply Kroil or equivalent then the next step would be an easy out. Then vice grips.
What does the other side look like?

I have easy out bits, but the alternative would be is to cut a line with a dremal and use a screwdriver

If cutting a slot for a screwdriver, any old screwdriver will probably not work. For real tough screws I get out my gunsmithing screwdrivers. The tip has parallel sides at the slot. I think for some reason this is called hollow ground screwdrivers. A regular screwdriver has the sides forming a very slight wedge shape and like to lever out of the slot and damage it. The parallel side tips of the hollow ground screwdriver can apply way more torque if you can really lean into it.

Grandfather did this I remember...he built airplanes as a machinist/tech. maybe someone can vouch.

he found a drill that was well short of thread size and drill a hole...then he’d enlarge the hole and thin the walls of the bolt gradually and carefully...Then vice grip and twist gingerly. If there was enough metal left, it decompressed the bolt against the wall of threads.

Looks like there is room for vice grips. Soak with penetrating oil and have at it with the vice grips.

Lot of tape to protect the finish of the dropout before filing, drilling, etc! Just my opinion...

I learned something new today! :) And, even at Amazon, those are not cheap -- but I hate straight-slot screws specifically due to lack of grip, this might be a neat purchase.

The head twisted off as you were unscrewing?

If so then do the file-slot thing first, you want to turn the remainder of the bolt *inwards*, getting away from whatever's binding. Mashing the threads won't let you do that, and if the head-end threads are torn up file them so they won't bind.

If that fails and you decide to drill, cut and file the end of the bolt flush with the dropout, then punch and drill.

Thanks for the advice all! Tried some of this last night. Had added more penetrating oil over the last couple days (didn't post until after I'd tried the freeze-out yesterday)

Vice grips just couldn't get enough purchase, either straight on or turned to the side sadly. Again wasn't using my brain, this bolt was way too tight in there to begin with. I guess it's my way back German heritage of getting something guten-tight.
:troll:

Filed a slot with my thinnest needle file from the set. Tried it shallow and no-go, every screwdriver or bit I had slipped. Filed it down to almost the dropout. Sides just weren't up to the torque (tried turning either way) and they started bowing/twisting out.
EDIT: Seems obvious now, but I wonder if I could've grabbed a thinner M5 nut, carefully threaded it on the remainder, THEN used a small screwdriver bit. Nut would've maybe held the "ears" together. Something to try if there's a next time...

Filed off the slot just about flush and started drilling. Too many dulled and snapped bits from the good set over the 15 years or so I've had them, so I need to run to the store and I'll grab a set of bits for metal. I have a set of Easy-Out type removers, but was going to take a peek at what they have at the store too.

Planning to drill out incrementally and try the extractors I have to the extent possible. May try warming up the whole dropout with the heat gun (expanding under heat), then hitting the hollowed out bolt inside with freeze-off (contraction), then an extractor. Seems like maybe the best combo of everything at my disposal at this point. Due to how tight it was to start, I'm not holding my breath it wont just have to be drilled out completely. But I've got to try right? Oh the indignity of having one threaded mount and one smooth bore!

The opposite side of the snapped bolt is nearly flush with the dropout, not recessed, but not even a full thread showing.

I was hoping some ID thread would be showing that a tap could be applied. Slow and easy at this point.

This worked for me with a broken off dropout adjustor screw. I wore a highly magnifying visor (to best center bit on bolt), and used new carbide bits. By the last bit, the remaining threads just fell out. I think the heat from drilling helps loosen things.

That's the beginning of the method guys who can weld will use - put a nut over the end of the broken bolt, weld the end to the inside of the nut.

Yeah my thought (after the fact) was file the slot, then thread on the nut to stabilize the sides of the slot, then try to unscrew. I did see some of those welding ideas but figured my skills of JB weld, solder, etc wouldn't be up to the task.

left hand drill bit
straight fluted extractor
proper tap wrench

when you're done you want this in your hand
https://cimg6.ibsrv.net/gimg/bikefor...d09e1a5701.jpg

https://cimg1.ibsrv.net/gimg/bikefor...39523b71f8.jpg
https://cimg3.ibsrv.net/gimg/bikefor...5165a05caf.jpg

good luck!

If it's a stainless screw they don't drill easy.

https://ttp-hard-drills.com/drilling-stainless-steel/

Stainless indeed doesn't drill easy! Took an hour off work (work from home helps) since I was trying freeze out in the garage, and the kids rooms are above the garage (so at night, gotta stay closed).

Took a long time to drill through with the 1/16" bit. Removed a lot, to clean and add some 3in1 as lube (maybe wrong choice?). Actually broke one 1/16" when I was adjusting my position (angle/pressure?). But cobalt bits got through there eventually. Stepping up size went nice and quick. Alignment was pretty good for eyeballing it.

Tried extractors with no luck until after I drilled 9/64" (3.6mm), and the second smallest "easy out" extractor pulled out the first half! Gotta figure out what to do with the back half but so far so good. Looks like it's maybe even broken through so maybe it'll come out easy or I can run a tap through - had a conference call so had to run back inside but hopeful for this evening!

https://cimg3.ibsrv.net/gimg/bikefor...16f8653b0c.jpg
initial 1/16" hole
https://cimg4.ibsrv.net/gimg/bikefor...59ac588b77.jpg
Back side 1/16" hole
https://cimg5.ibsrv.net/gimg/bikefor...f9b0cc30dc.jpg
Getting bigger...
https://cimg8.ibsrv.net/gimg/bikefor...32ebaed445.jpg
Bigger rear side
https://cimg9.ibsrv.net/gimg/bikefor...9f2fba8b2a.jpg
Success for front half!
https://cimg0.ibsrv.net/gimg/bikefor...5c300ed2db.jpg
Removed chunk
https://cimg1.ibsrv.net/gimg/bikefor...475e5776e5.jpg
Removed

...for a fender stay mount like that:

1. even if you do go off center and hit some of the threading on one side of the hole, it's usually not enough to matter much. The machine screw that holds that fender stay in place doesn't carry much load with a fender.

2. if you are mounting something that will carry a load, like a rack, and you're worried about the damaged threads, it's not a big deal to drill out the stay eye a size larger and re-tap it to fit a larger machine screw.

But yeah, I usually just assume that if a machine screw is in there tight enough that turning it snapped off the head, drilling is my best bet for removal. In the smaller bit sizes, those bits that are coated with miracle space age titanium nitride don't cost that much more, and seem to last longer in use for me.

https://cimg8.ibsrv.net/gimg/bikefor...08124542f0.jpg

excellent progress! be patient!

You can use a Torx bit for an "EZ" out too, needs to be a quality one, Milwaukee, Dewalt, Makita, etc. you can press them in with a C clamp to keep from pounding on them.

And they have dedicated ones that are basically the same as but probably tougher.

Lisle 61980 screw extractor set and the like.

The heat from the welding will probably loosen the bolt too.

If push comes to shove and you end up damaging the threads, not all is lost.

I prefer not threading into those dropout eyelets, sometimes I drill out the threads. Best to use a bolt and nylok nut for that application, they'll never loose, and if they seize a hacksaw or dremel will remove them.