Sheared-off bolt extraction

[michael adams]

Sorry maybe I've misunderstood. But what's wrong with using nut splitters?

michael adams

...

[Steve Walker]

Yup, the one I've got would just about go down to that. I have definitely used it on damaged exhaust stud on a 1970s motorbike and I'm pretty sure that was around that size.

SteveW

[newshound]

Fine if there is room to use them. Each one only covers a limited range of sizes though. It is one tool that I have never felt the need to buy.

Another good method is to cut along a sector just missing the threads using a slitting disk on a Dremel or clone. Then use a chisel to break the remaining metal by putting it in tension.

[gopalansampath]

"Not for the welding but if you really mean that there is 15mm sticking out then that should be enough to get some decent self locking pliers on ('Mole grips') after giving the thread a good soaking of Plus Gas." Also smacking hard with a mallet a few times will help loosen any hard set rust

[michael adams]

Why would anyone need to "extract" a "broken off" bolt head ?

If it's already "broken off", then presumably it fell to the floor and ended up in the bin.

Which word or words in the two word phrase "broken off" are you having the biggest difficulty in understanding, Mike ?

Tell you what Mike, if you're still having trouble understanding any of this, why not show this post to somebody else ?

michael adams

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[RobertL]

it is probably obvious to everyone but I'll say it anyway: once the plus gas is applied and the moles are gripped then try to wiggle the bolt alternately clock and anticlockwiwse to help to free it. Don't just try to unscrew it.

Robert

[T i m]

That could also be 'Eastern European / Indian / African style from what I've seen on Youtube and the TV. ;-)

I think I've even seen then rolled on it's side into a slight ditch?

My mate had and successfully used one of the rollover frames when he was restoring his 3L Capri. ;-)

Cheers, T i m

[T i m]

As you stumble round trying to help ... why would you (even try to use) use a stud extractor, designed for when a stud or bolt has sheared off below (or so close to noting else will grip), when you can still get hold of (what has become) the stud?

Cheers, T i m

[Cursitor Doom]

Those rotisseries are brill for working on body shells, but somewhat useless for complete cars owing to the various fluids pissing out everywhere.

[Chris]

Anyone used these? Any good?

Update: that remaining bit of stud has now been ground off. I simply could not get the damn thing to budge as much as a mil in either direction, even with a thumping great pair of stilsons as a last resort. So I'm now in the process of drilling the rest of the shank out. Most likely solution now is going to be either NP's suggestion - or scrapping the car. ;-)

[Chris]

?? Arc welding rods *are* filler rods.

[T i m]

Quite. In mates case it was totally suitable because it was really for working on the shell.

Cheers, T i m

[T i m]

Not those specifically but I have a set of stud extractors like that and have used them fairly successfully several times.

Hmmm, assuming the Stilsons were still gripping the stud but you couldn't get it to break free then *in theory* you could have been able to push it hard enough that you would shear it off?

The problem is ... if you really were gripping the stud hard enough that it simply wasn't allowing you to move the stud at all (or shear off) , I wouldn't have thought a stud extractor was guaranteed to help. ;-(

However, if you can make a nice clean and suitably sized hole down the middle (big enough to get a big enough extractor in but not just be at the tip of the extractor) and carry on with the Plus Gas and heat, the remains of the stud might 'give' enough to get it to break free.

Failing that and assuming there is still some reasonable sidewall to the stud, drill a fine hole down the threadline, and then go back to the extractor / Plus Gas / Heat.

Failing that, is there anything stopping you drilling it out and tapping it M10 (for M10 x 1.5, 8.4mm) or drilling it out and getting it Helicoiled?

What exactly does this bolt do? e.g. Is it structural?

Cheers, T i m

[T i m]

The thing is it's sometimes easy to forget the things you just do instinctively, so worthy of mention. ;-)

From the updates / feedback from the OP we have had so far I'm not sure he has had say Mole grips on it to be able to do that easily.

As has been mentioned ... once the stud had been soaked and heated a few times (over a few days if possible) and then in theory, the stud could be gripped so hard with a suitably shaped and size Mole grips that if it didn't break free it would shear off?

Cheers, T i m

[Chris]

Yes, it was totally solid and would have sheared anyway.

Correct. It's a pig whatever method I employ. A pal of mine has one of these EZ-out things he will lend me so it won't cost me anything to try it tomorrow.

Wow! The ideas just keep on comin'. More than a dozen ways to skin this mule it seems.

Kind of, yes (trailing arm/radius arm). I must do it right or not at all.

I'll report back in due course......

[The Other Mike]

Nope, technically they are called (consumable) electrodes.

No need to take my word for it, this is what the experts at The Welding Institute near Cambridge say

or what ESAB say

or what Murex say

or what Oerlikon say

[The Other Mike]

No they are shit, they will often break, leaving a hard impossible to drill stub left in the hole. Spark erosion removal will not be an option in your case.

With no stub left you need this type to do the job although 8mm is right on the bottom limit for their use

Alternatively this type is far less prone to breakage unlike the screwfix ones.

Too late now but the key thing is heat, proper penetrating fluid and dwell time.

Oxy-acetylene or oxy-propane preferably, butane or propane at a push. Penetrating fluid, anything but WD40 or a clone. Loctite freeze & release, Plusgas or Wurth

Welding a nut on with a mig torch can be done totally blind IF you had left a stub.

[michael adams]

Dear me. Now lets see, they're not made of chocolate are they ?

Nope. Seems not.

michael adams

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[Alan Dawes]

That's because that stud is part of the jacking point and was spot welded to the chasis during manufacture so that it could not come out.

Alan

[Chris]

Certainly not on this car! I removed the identical one on the opposite side with little difficulty and it's just a pretty standard UNF bolt (albeit with a hole through the head for locking wire so it can't come undone in normal use).