What a weekend, almost got the last few jobs done on the 'Buse engine but then snapped two bolts on the clutch cover. Oil baffle went in like a dream (didn't have to pull the clutch out as I had expected). Soaked the sheared bolts in WD and drilled them out but in spite of greatest of care the extractor snapped. Tried twice, probably in denial, so have f****d up both of them. Any one have any ideas on how to remove them. Will I need a specialist to do it, if so any recommendations around Uxbridge, Slough, Windsor way?

All ideas gratefully received!!

Yours, Clive.

Had something similiar happen to a cylinder head once, took it to a local engineers place, and they removed it by using a process called spark erosion, cant remember how much it was, that will probably be your best bet

ye olde stud extractor snapping!! LOL - never had that happen before!!

probably too late now but drilling out the bolts with a drill that is just the same size less thread and then picking out the threads or running a tap down the holes.

but with extractors, you either would need a harder drill - see mullered roll pin thread - or spark errosion.

If you're going to have it done with spark erosion, you will save heaps of money by good preparation. Strip everything down until all that's left is the piece with the broken stud/extractor in it - and I mean EVERYTHING!

The spark erosion machines I've seen run the spark under a cooling/cleaning liquid (some even pump the fluid through the electrode) and it gets everywhere. If you're talking about an assembled engine then you probably don't want the coolant all through the crankcase & cylinders!

If the engineering shop don't have to do any preparation other than putting it on the machine then it shouldn't be too expensive - all they'll do is start the machine and go and do something else until it's finished.

Probably not what you want to hear though, considering that you'd almost finished the assembly...
... talk to the shop before you do anything, though. They may well say otherwise.

We have a couple of spark erosion machines and as previous posts say you definetly should strip it down as best as possible before it goes on the machine. The dialectric fluid used in the process is comparable to paraffin except with a much lower flashpoint. It gets absolutely everywhere and is a pain in the ar*e to get rid of. The best method we have found is to simply rinse using warm water and washing up liquid.

If you cant find anyone in your area to do it and are prepared to post it, i can do it for you for free of charge.

Chris.

[Edited on 12/5/08 by Nosbod]

Has anyone ever removed a stud with an extractor?

There should be someone on Slough Trading Estate - Yellow Pages or Google.
Failing that ask Tunes Engineering Supplies 01753 536811 as they will supply most of those guys and are generally helpful.
Cheers, Pewe.

Both sheared threads are in the engine casing (clutch cover bolts) so it sounds like a complete stripdown of the engine if I want to use spark erosion! I really really DONT want to do that unless there is absolutely no other option! Is drilling out the thread extractor viable?

Yes. You need a Dremel, some (read lots!) 3-4mm tungsten carbide burrs and a very steady hand! Then, it's worth helicoiling the hole as chances are you'll damage the existing threads. I have to admit that I've done exactly the same as you before and so wish that I'd done this in the first place and not nessed around with stud extractors! They're utter crap unless you buy some that are top quality!

You might be able try the 'MIG welding a nut on the stub of the sheared stud' method if there is any stud still showing. As long as there has been a bit of stud showing I've never failed with this method - the heat frees the stud off and it comes out using the nut that you have welded down the middle.

Cheers

mark

Ahh, okay, this is looking a little more promising. I spoke with PDQ Motorcycle Developments and they told me that they attempt to shatter the embedded extractor with good quality punches which must be constantly sharpened and more than one of which will be destroyed in the process. The brittle nature of the extractor means they will shatter (as I found out). This combined with Coose's suggestion with the carbide burrs may be a viable solution! PDQs main concern was the amount of time thread extraction takes but given it will be my own time it shouldn't be too expensive but will certainly slow down my build!

Hmmm - I'm not sure I'd want to hammer against a super-hard piece of steel screwed into aluminium alloy! I suspect that there would be a very high chance of trashing the casting too, either by bending or cracking.

If it was mine, I'd strip it and get it eroded out - at least then all I'd have to do is clean up the thread and wind in a new stud. However, I do realise what a PITA that would be for you - but imagine the consequences of wrecking the casing.

The dremel and lots of grinding tips would do the job, but you'd have to be careful where the grinding dust goes as it will be VERY abrasive - not nice in an engine! The tips would probably skid around too, messing up the threads.

[Edited on 12/5/08 by David Jenkins]

I guess it depends how big the stud is, but could you drill a row of small holes in it, whack in a chunky screwdriver and use a mole grip to twist it? I have a couple of screwdrivers with square profile sharts... just an idea

I wouldn;t try and "shatter" the Extractor out of the Hole - Not a good plan. Far to many bits of flying sharp metal for my liking - If you do ensure you wear very good eye protection.

I would go down the route of - Spark errode if I had the money skill & time.

or

Take the cheaper option of the dremel, or Air Die grinder and slowly work it out. Buy the best Tunsgstan carbide tips you can afford. Then Re-tap or fit a Hellicoil - This is the one i'd use

or

Go to a good tool mearchant (lathe tools etc) and buy a tungstane Carbide drill bit and drill it out and as said above fit a hellicoil. Problem with this method is if the casing is very soft good chance the drill will wander into the softermaterial


BTW - I gave up using "easyout" (male type) Extractor but do use these http://www.uktools.com/product_info.php?products_id=11525 But this only reall works on chewed Nuts - (100% success so far) - Did manage to get them to fit an M10 Bolt and wound out 7 knackered bolts.

Hi Clive

I have had to do this once before and I used a dremel (as coose said) but I used one of the small ball end diamond engraving tips to dig the extractor out. I dug into what was left of the bolt around the extractor and then wiggled it out with a small screwdriver. It takes a bit of patience but It doesn't make as much mess or damage the thread like a burr would.

I hope this helps.
Sonja

I droped into my local tool shop but the hardest burr they had was an aluminium oxide burr. I'm told aluminium oxide is pretty damn hard. Will this do? I found two carbide burrs, one was not listed as suitable for any metal, the other for mild steel only while the Aluminium Oxide appeared to be graded for any steel.

Road Warrior, how did the diamond tipped engraving tip do, did it last the course or did you get through a few of them?

i would try the weld method....

i would just TIG weld a bolt to the studd

(testing on the remaining part wich you have if it holds..)

then just try to force it backwards...

It they are not adjacent studs then there is a good chance that the cover will not leak if fitted with a gasket and silicone gasket goo. The cover is not structural. It's worth a try even if you are putting off the inevitable trip to a spark eroders with stripped down crankcases.
As you now know to your cost, Easyout stud extractors are not meant to remove seized or tightened studs, just broken off ones.

Clive

I used one tip on one extractor. I'm pretty sure is was this size. here

Try to go around the extractor if possible if there is room and it will last longer. They are not too expensive so it might be worth a try.

Hi Phil,

Unfortunately they are adjacent, albeit close together and at the top of the casing/cover so your idea may work, but I would rather avoid it unless there is absolutely no other option than to completely strip down the engine.

Yours, Clive.

Road Warrior,

I've ordered some via your link. The blurb specifically states they are suitable for hardened steel so thanks for the tip! (if you excuse the pun!)

Yours, Clive.

Actualy,.... TKSs idea isn't bad. Weld a nut on it! Has anyone tried that before? Any luck or advice?

yep I was amazed how well the welding a nut on works.

Are there any threads of the bolt left above the cassing ? It helps no end if you havnt ground it flush.

They're not quite flush, one stands off about 1mm and the other about 2mm. Do you think that will be enough?

Perhaps you didn't notice my earlier post?

Yes 1or 2mm sticking out will be fine.

Cheers

Mark

Fencewrecker got a similar seized bolt out of his Mazda engine casing with the welded nut trick last night so I'm definitely going to fire up the welder and have a go. There is slighty more than a 90 degree angle between the bolt axis and the mating face (gasket surface) but again Fencewrecker came up with the suggestion of chamfering the nut so I'll do that to stop the nut face gouging the mating face of the casing. Wish me luck!

What a weekend! Bought M6 nuts and bolts to practice welding nuts to bolts but quickly realised MIG was striking to the nut while I was trying to strike it to the bolt. Switched to M8 nuts and was successful so began welding nuts to the two siezed bolts. Got good welds every time but shaft of bolts sheared again each time. Probably because I had drilled them out for the thread extractor. When they sheared however the broken bits of thread extractor came with them! So a minor success at least.

Eventually gave up the welded nut approach and decided heart-in-mouth to drill and tap out the sheared shafts. Drilled them out 3m then 4mm then 5mm and then put through an M6 tap.

Success, and the internal threads are still good! What a relief!!!

I won't make the mistake of using thread extractors again! I reckon the welded nut trick would have worked if the shafts had not been driled out! Certainly a new way of removing broken thread extractors!!