Author Topic: Extracting Broken Studs! Tips?  (Read 1807 times)

Offline LJ.

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Extracting Broken Studs! Tips?
« on: 15.12. 2010 21:37 »
Help! I'm pulling hair, I'm grinding my teeth, My world has come to an end!

Stud extraction! How do you do it? I've got as far as screwing in an extractor a '2 CV' whatever that is, but its a 'Good' qualtity made item from Germany. Snag is... it is bending and I'm afraid it'll break. I'm wondering if I should leave this now until I'm ready to heat up the case to take out old worn bearings. I'm looking for tips to consider and maybe this will be a good thread to anyone else who is having these problems.

Has anyone tried this?... Looks exciting...  ;D

Quote
Get two visegrips and a BIG battery (don't waste yer time with some battery charger) and some jumper cables. You clamp one of the vise grips to the stuck bolt/stud/screw very tightly on a shiny part so you got a good connection. The other vise grip you clamp very tightly on a close by ground (don't clamp on a rear brake bleeder and use the stock ground in the front). You connect both the jumpers to the battery and the other end to the stuck bolt vise grip. Then the fun part, you QUICKLY clamp the other remaining battery jumper to the ground and there will be a BIG spark! Wait 2-3 seconds and take it off and try to wiggle the part, if nothing happens try again. It will eventually loosen the part, because corrosion has more resistance than good clean metal. and you will blast the rust/ oxide out with the maybe 4-600 amps you are putting through it. Sometimes there will be a small puff of smoke. Polarity doesn't seem to make any difference.
Ride Safely Lads! LJ.
**********************
1940 BSA M20 500cc Girder/Rigid- (SOLD)
1947 BSA M21 600cc Girder/Rigid-Green
1949 BSA A7   500cc Girder/Plunger Star Twin-(SOLD)
1953 BSA B33  500cc Teles/Plunger-Maroon
1961 BSA A10  650cc Golden Flash-Blue
1961 BSA A10  650cc Golden Flash-Red

Offline a10gf

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Re: Extracting Broken Studs! Tips?
« Reply #1 on: 15.12. 2010 21:55 »
These things are a challenge, practical as well as patience. You seem to have gotten a good hold of the offender. But the stud may have expanded slightly and has a good grip.

What I'd do: heat the case, then a spray on the stud from an electronics cooling spraycan, repeat heat\cold many times as necessary, while gently applying force to the extractor. A dose of crc and a few -small- hammer hits as well now and then.

And apply lots of patience, then it won't break, and hopefully come loose with a satisfying small 'klick'.

Good luck, and remember, there is a newly implemented forum-ban on stories and photos depicting broken extractor inside broken stud !  *smile*

A10 GF '53 My A10 website
"Success only gets you a ticket to a much more difficult task"

Online bsa-bill

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Re: Extracting Broken Studs! Tips?
« Reply #2 on: 15.12. 2010 22:06 »
Oh Oh LJ , hope the photo's gives a wrong impression but it looks like it's drilled off centre which is not good, extractor will be applying uneven pressure and forcing the thin section out making it tighter - hope I'm wrong.
A10gf's way heat/cold good advice but take it easy.
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Offline Stu55Flash

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Re: Extracting Broken Studs! Tips?
« Reply #3 on: 15.12. 2010 22:17 »
The best way I've found is to stick weld a washer through the hole onto the broken stud. Then weld a nut through the hole again onto the washer. The heat frees the stud and the washer protects the other parts. I've never had much luck with both Easyouts and the a the square type extractors.

Stu
"Keep a distance from lady "L" drivers in cars. Some are not mechanically minded, are slow to acquire road sense, an are apt to panic..." The Pitman Book of the BSA Twins.
Golden Flash Plunger 1955, Francis Barnett Falcon 67 1954, Ferguson TEA Tractor 1951. Looking for another project!

Offline sinbad

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Re: Extracting Broken Studs! Tips?
« Reply #4 on: 15.12. 2010 23:24 »
You might try (plus gas)and soak the stud in it for a few days,you do need patience.After that warm the crankcase take a small pin punch and gently try knocking the stud in and outward to get some movement,
I removed a seized  piston with with this product but it takes time.
Rod
1960 A10                             1998 Honda Cb 500
1953 sunbeam s7                   1988 Mz 250
1953 Nsu Consul 500 single        Jzr cx 500 Trike

Offline chaterlea25

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Re: Extracting Broken Studs! Tips?
« Reply #5 on: 15.12. 2010 23:29 »
Hi LJ,
I have found those taper stud extractors to be useless *sad2*
If you can get hold of some of this stuff its GREAT *smile*
http://www.kenteurope.com/uk/datasheets/84599.pdf

If your drilled hole has gone off centre  make up a jig measuring from the good bolt holes or the primary case to get the centres bang on, make it from at least 1/2in thick steel, bolt this onto the case using the good bolt holes
Then use an end mill to bore away the damaged stud, the jig will keep the cutter central on the broken stud
All this assumes you have a decent pillar drill and can clamp the case to the table ????
Or fiind someone who has *idea*
Another method of removalis spark erosion

I quite like the idea of using the battery *smile* One word of warning  DO NOT MAKE SPARKS AT THE BATTERY TERMINALS *eek* *eek*

HTH
John O R
1961 Super Rocket
1963 RGS (ongoing)

Offline a101960

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Re: Extracting Broken Studs! Tips?
« Reply #6 on: 15.12. 2010 23:48 »
LJ

I think that there is only one satisfactory solution to this problem. If you persist in trying to extract that stud you will be unlikely to succeed. Stop right now! There is no such thing as a good quality stud extractor no matter where they come from, they are very brittle and very likely to shear. Any competent engineer will tell you that they will only make matters worse. I have had a lot of experience with this type of problem when I worked on aircraft winches. Due to electrolytic action studs, bolts, and screws shearing was a constant problem. Take your casting to an engineering company and get it removed properly by spark erosion. There is no other way of doing this job safely. Be mindful of the fact that if the extractor does shear (and it surely will) then you will have no chance of drilling the extractor out.

John

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Re: Extracting Broken Studs! Tips?
« Reply #7 on: 16.12. 2010 06:19 »
Like both Johns I have never had any luck at all with so-called extractors. A jig and an end mill would recover things I think but spark erosion is certainly best. Can't remember on a B if it's a blind hole but am assuming it must be?
What I have usually done in similar circs is dress the uneven surface of the offending item with a jig and mill to get a flat surface, centre popped it dead centre and drilled - using a pillar drill or miller - going up in size by the smallest possible increments until the hole is a fraction under the minor diameter, then picked out the collapsing remnants - really little more than a coil of wire - with a scribe.  I have successfully done a few this way - but never without heart in mouth at some point along the way. It's hard.
Bill

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Re: Extracting Broken Studs! Tips?
« Reply #8 on: 16.12. 2010 11:44 »
I use a Dremel tool with the long flexible drive so all you have in your hand is the pencil end of the drive so you have really good control of it.
Drill the hole bigger. one size at a time till it is getting close to the minor diameter of the hole.
Make yourself comfortable, fit a carbide cutter in the end of the Dremel and cut all of the remaining stud out.
Slowly slowly.
Eventually there will be noting left in the hole but the thread of the stud and you will be able to wind it out with a pair of tweezers.
If you do not already have one of those big magnifying glasses on a stand with a light in it, now is a good time to buy one.
Eventually you will need it so you may as well get used to using it now while you have good eyes.

Very important.
Buy only a Dremel and nothing but a Dremel.
None of the cheapie knock offs have the precise control of a Dremel.
They are good enough to clean & polish but not good enough to do this type of work.
Bike Beesa
Trevor

Offline LJ.

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Re: Extracting Broken Studs! Tips?
« Reply #9 on: 17.12. 2010 11:08 »
Thanks for the tips! Got it sorted now... I was reading through your responses last night and just had to go out to the shed and work on it. In spite of having a cold and it was cold in the shed as well, I opted to nibble away at the broken stud, I was just too nervous to carry on with the stud extractor. It did take a while but the shed soon warmed up and had the radio on, so I was well entertained for the evening and it felt better than sitting in front of a computer screen.

The original hole was a bit off centre, but not so much that it was fouling the threads. I aimed to cut a slot so that I could try using a screw driver to budge the stud. The stud had sat in a good pool of WD40 for a few hours. I then nibbled away with a Dremel as Trevor suggested. Welding is not my thing although I wish it was, one day maybe? The hardest part was to determine just how close to get to the threads so that I could then just pull out the 'thread coil'... ha ha, this was not to be! It was a painstaking long effort with a needle and tweezers before the last crescent of metal was pulled out. I found it helped in having a straight cut bolt which help in lifting the shads out.

Having finally got the job done, it really felt satisfying to have successfully saved the original threads (Talk about rivet counting Ha! ) and they are in pretty good condition to be able to take a new bolt along with plenty of copper grease. I think the problem was that the stuck stud was just a tad tight in its fit, the screw in extractor must have pushed out the studs sides making it a tighter fit still.

All in all... a satisfying evening! Thanks for the tips...

P.S. Got the dating certificate this morning to say the B33 has matching numbers and was dispatched to Craze Brothers in Bournemouth 26th August 1953, this surprises me as the date on inside of the timing area states the engine was made on the 6/8/53, seems that BSA did not waste much time in shifting the newly built bikes into the show rooms.
Ride Safely Lads! LJ.
**********************
1940 BSA M20 500cc Girder/Rigid- (SOLD)
1947 BSA M21 600cc Girder/Rigid-Green
1949 BSA A7   500cc Girder/Plunger Star Twin-(SOLD)
1953 BSA B33  500cc Teles/Plunger-Maroon
1961 BSA A10  650cc Golden Flash-Blue
1961 BSA A10  650cc Golden Flash-Red

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Re: Extracting Broken Studs! Tips?
« Reply #10 on: 17.12. 2010 12:01 »
Brilliant LJ! One of the most satisfying feelings when there's a happy ending and an intact thread.
It was having the radio on wot dun it - you weren't put off by the noise of your heart thumping it's way to your mouth!
I'd run a bottom tap down it now to get it squeaky clean and as good as it can be for the next 57 years. . .
There isn't anything I love more than my B31, really hope yours gets you the same way.
Bill

Offline brackenfel

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Re: Extracting Broken Studs! Tips?
« Reply #11 on: 17.12. 2010 12:57 »
Well Done LJ...!!

Glad you got it sorted without mishap..
As for the B33 - mine was registered May 1954, engine number BB33 3722  so I guess yours is spot on for the previous year.. Mine has April '54 stamped on the case so your thought about them flying off the showroom floor seems pretty correct....

Cheers,
Adrian
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Online bsa-bill

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Re: Extracting Broken Studs! Tips?
« Reply #12 on: 17.12. 2010 15:34 »
Nice one, a man with patience, something SWMBO reckons I am seriously short of
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Offline dodmo

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Re: Extracting Broken Studs! Tips?
« Reply #13 on: 17.12. 2010 20:36 »
I'm a believer in using a mini-mig welder.

For small diameter studs:
  • drill a shallow hole with a safe diameter (ie a good bit smaller than the stud)
  • Insert a suitable bent nail and tack weld it in.
  • The heat will almost always break the seizure and you can twiddle out the stud.
For larger diameter studs:
  • Use a small bolt
  • undo with a socket.

If the stud still extends above the hole then a slightly over size nut slipped over the end and welded will do it (works well on Japanese exhaust clamp studs)

Note: all my experience using this method relates to steel studs in alloy. I've never used it with cast iron

Cheers
Dodmo