Suitable Welder for broken stud extraction

[AndyStobbs]

Guy asks about a welder and gets lessons on bolt removal. You'll get enough heat in with 100 amps. I use this method on m12 wheel studs all the time with a 135A welder running at less than full power. Its not too late to shock the bolts. You could shock them prior to welding and again after the weld, while they're still hot. Be mindful where you put the earth clamp. Avoid any sealing faces.

 

[normspanners]

Its not too late to shock the bolts. You could shock them prior to welding and again after the weld, while they're still hot. Be mindful where you put the earth clamp. Avoid any sealing faces.

And now a lesson in bolt removal ? HA, Thing is Andy If he had got them out in the first instance he wouldn't have needed to resort to welding, But if it has rounded/split a torx they must be dammed tight and from my experience having welded many, the stud /bolt tends to shear just under the head of the bolt and if it is a low clearance engine compartment you are stuffed for getting the head up enough to remove it. That is why I like to try and reshape the bolt head without vastly changing the steel structure, by welding I had one that I had to drive a wedge in enough to get a hacksaw blade in and cut the studs under the head!

 

[AndyStobbs]

E12 is a pretty puny head for a 12mm bolt. Suitable at first assembly when its all new and clean. But after a few years rust and corrosion, I dont think its unreasonable for the E12 head to shear off. Agreed if its tight in the engine bay then you're in for fun. Often the tightness precludes getting a hammer in anyway. On a normal headed bolt it can sometimes be a bonus if a bolt snaps.

 

[sean greenan]

I doubt the heat from the mig would reach the depths of the threads. Some head bolts are stretch bolts along with bimetal reaction, woodyv8 suggestion may the a safer bet just in case they might shear at a lower point and not given you any stump to work on. A fancy tool called a mini ductor II (USA) a hand held induction heater will un seize alot. A lot of mechanics would want one. But cost alot. ($500).

 

[dannyp]

weding nuts on head bolts has never worked for me

those spline had bolts can be right BA$TARDS tho, usalyy it centerpunch the top and get a nice cobalt drill in plenty of cutting oil, low revs nd much down through the center of the bolt.

old magnets are good for swarf colection and retention.

often find they ping when break through then you can lift the head off over the now studs, the studs are then ually a pice of **** to remove like wind out with fingers once ot twice i've have to use molegrips

 

[Woody.v8]

weding nuts on head bolts has never worked for me

those spline had bolts can be right BA$TARDS tho, usalyy it centerpunch the top and get a nice cobalt drill in plenty of cutting oil, low revs nd much down through the center of the bolt.

old magnets are good for swarf colection and retention.

often find they ping when break through then you can lift the head off over the now studs, the studs are then ually a pice of **** to remove like wind out with fingers once ot twice i've have to use molegrips

I have done it this way over a dozen times and its never failed yet (just to be clear the heads had been mullerd by other peoples hamfisted attempts)

 

[Paul99]

I've lost count the number of times welding a nut on has got me out of trouble. It's a bit of a pain with an arc welder but it's doable unless in a really tight spot...

I once took an old mower part into a local semi-retired engineer / fabricator to get a 3 maybe 3.5mm left hand thread bolt that had sheared flush drilled out and re-tapped. The old guy took one look then heads for the welder . Within about 2mins he'd built up a stalk of weld long enough to grab with a mole grips a light twist and out it came . To say I was impressed was an understatement I would never even considered attempting it especially using a big old oil cooled welder and full length 3.25mm rods that he did - I still can't work out how he managed it. It clearly wasn't the first time he done something like that - TBH it was a joy to watch someone show some real skill.

 

[normspanners]

I've lost count the number of times welding a nut on has got me out of trouble. It's a bit of a pain with an arc welder but it's doable unless in a really tight spot...

I once took an old mower part into a local semi-retired engineer / fabricator to get a 3 maybe 3.5mm left hand thread bolt that had sheared flush drilled out and re-tapped. The old guy took one look then heads for the welder . Within about 2mins he'd built up a stalk of weld long enough to grab with a mole grips a light twist and out it came . To say I was impressed was an understatement I would never even considered attempting it especially using a big old oil cooled welder and full length 3.25mm rods that he did - I still can't work out how he managed it. It clearly wasn't the first time he done something like that - TBH it was a joy to watch someone show some real skill.

That is exactly how I have got countless studs out it is my method of choice
apart from I usually build up the stud then pop a 10mm nut on the built up stub then I weld the nut to the stub, but the pressure is usually off the the broken stud.
I have got many a broken bleed nipple out of ally / cast calipers etc with this method

 

[fxmaster]

Just an update on this - may be useful to someone else in the same predicament:-

Firstly thanks to everyone for your replys and suggestions.

Unfortunately I couldnt get someone to weld any nuts on, and a 200A welder as someone suggested was just a bit mor expensive that I planned on spending at the moment. So resorted to the drilling method.

I got some decent cobalt drills to do this.

I pushed some paper towels in and around oil holes and spaces around the cam shaft
Then placed a sheet over the over the engine which had a small hole cut it in it to lie over the bolt head.
This way most of the metal removed by drilling ends up on the top of the sheet.
I also used a magnet to pick up the metal pieces from time to time whilst drilling.

Centre punched the centre of the bolt head then used a 3mm drill to drill down just passed the bottom of the bolt head.
Stepped up to a 5mm drill and drilled down to the bottom of the first hole
Then used a 10.5mm drill to drill down to the point where there is insufficient metal left on the bolt head to hold the tension in the bolt and you actually hear the head of the bolt 'snap' off and start spinning with the drill.

The washer under the bolt head just lifts of and the remaining bolt stud just turns out wth a pair of pliers on it.

Note use cutting oil on the drill(s) from time to aid drilling.

Had to do three bolts like this - the other 7 came off normally with a socket.
Total time to drill all three out was approx 45 minutes taking my time.
The Cobalt driills drilled out these hardened bolts no problem at all.

If anyone else has to do this just watch the meatal bits from drilling dont go anywhere you dont want them to.

 

[normspanners]

Well done, BTW was it a Merc ?

 

[fxmaster]

Well done, BTW was it a Merc ?

ir was a Vauchall Zafira (x16xel engine)

 

[MINGER]

Looking for a suitable Mig welder to weld nuts onto some broken cylinder head bolts on my car (bolt heads have rounded).
One solution I've been told is to weld a nut onto the rounded head.
I've never done welding before but reckon with some practice first I could do this.
The bolt studs are approx 12mm in diameter.
How many amps would a suitable mig welder need to be to put sufficient heat in do this. Bear in mind these studs are tight/maybe seized; only rounded because of this I guess and broke a good socket in my attempts to remove.

Thanks in advance

Have you tried a metrinch spanner? Or is it too rounded?

Or better still a metrinch socket with an impact wrench?

 

[MINGER]

DUH Should have read all the posts ........But perhaps next time use metrinch spannerr/socket, they are a lot less likely to round off the nuts.

 

[normspanners]

ir was a Vauchall Zafira (x16xel engine)

unusual for that engine, to be that tight for some reason I have had problems with mercs
especially 5cyl sprinters but they are the other way round with a female torx headed bolts being VERY tight.
I have had to use the hammer method and the heat on a couple