Removing a snapped bolt

Right chaps, first PLEASE accept my apologies as this doesn't refer to a problem with a beloved Triumph. A neighbour of mine called this morning, it seems he has snapped a bolt in the block while trying to remove a side cover on his Kwakazowi Z750 because there was an oil leak so he was going to change the gasket. Went round and had a look, oh dear. There is about 5mm of the bolt sticking out of the block and about 15mm of the bolt stuck solid in the block. Tried with some mole grips but it well and truly stuck. He says "wondered why it got tighter as I un-did it". He swapped the original bolts for stainless bolts last year so I'm guessing it's picked up some swarf or something or has tried to cut it's own thread on the way out. I asked him if he put any anti-scuffing paste on the bolts when he put the new bolts in and his reply was "WTF is anti-scuffing paste", (he's NO engineering knowledge by the way). So the problem how the **** do you get it out with out without a major strip down or removing the engine. As the offending objet is stainless steel, if will be a real bar steward to drill in-situ with a Black and Decker without boron carbide drills.
So chaps I respectfully ask can your please put thinking caps on and come up with a suitable method.

 

Hi Biglad.
Thanks for the tips chap.
1. There isn't enough stud left in to weld anything on to plus the heat from welding might just be too much and damage the casing, it being an alloy.
2. I've tried drilling stainless steel with a bog standard Black and Decker type thing but the speed control is too random and normal high speed steel drills tend to burn out quickly and are also prone to snapping. I remember when I worked in engineering that we used boron carbide drill bits for stainless because they take a much higher temperatures so stay sharp and last longer, I've never come across left handed drill bits before but I see the logic.
3. My idea exactly, drill it fairly close to size then use a stud extractor/Easi-Out to drag out what's left then re-tap the hole to clean out any crap and repair the thread.
4. The remaining bit of the stud has seen far too much damage from mole grips. I guess the diameter is somewhat 'reduced' from the original 6mm to more like 4mm so cutting a slot in it will only end up snapping off what's left.

I've done similar jobs as an maintenance engineer but it was much easier as you could either take it all apart and set it up on a machine or, use a magnet mounted drill and do it in-situ. Just a shame I don't have access to that kind of kit anymore.
I've since found out that he got the bolts from a 'specialist supplier' so I checked the website, it seems they supply marine fittings and the bolts are 316 stainless which is pretty hard stuff. He should have got the bolts from a bike company instead, but he is a bit of a pillock.

Glad to say it ain't my bike so I'm not too fussed about extra damage and it serves him right for being a pillock anyway. But, thanks again and much appreciated.

 

Hi jtd. Yes you can weld stainless, but the heat might be a bit of a problem as the casing is an alloy and you need about 1200 deg C to weld stainless. Good idea though.
PS. Not a great fan of welding mild steel to stainless, it usually has corrosion problems latter on as you burn off some of the chromium in the stainless and it's the chromium that keeps it 'stainless'

 

There's nothing wrong with stainless fasteners provided that
1. You use a good quality anti-scuff paste like ROCOL ASP when you put them in to prevent 'gawling'.
2. You get the correct stainless fastenings for the job. In this case he bought marine grade stainless fasteners because he's a pillock. He should have gone to either an engineering or bike specific supplier instead of a marine fasteners supplier.
Marine grade stainless (316 grade) contains a high percentage of chromium and therefore quite hard where as normal stainless fasteners don't have as much chromium and so are have higher tensile strength (toughness), therfore less likely to snap. Another 'problem' can be caused if you use stainless fasteners with mild steel (carbon steel) as this can get galvanic corrosion between the stainless bolt, washer, nut or plate etc.
I used to work with corrosion and materials specialists so all this really clever stuff rubbed off on me

 

Had a quick run through the link, say's it all really. What people forget is that the design engineer spec's a material, whether it's fasteners or anything really on its mechanical properties and suitability for purpose. The problems come when someone decides that the cost will be to high so they 'suggest' that the spec's are lowered to the minimum while maintaining safety standards. The poor unsuspecting punter who probably has no in depth experience of engineering design or mechanical engineering principles decides to replace items such as fasteners and innocently buys the wrong thing because they are easily baffled by the techno bull$#!t, it looks nice and shiny, or simply, they don't know any better, as in the case of my neighbour with the busted bolt who is a high school teacher, (and a bit of a pillock to boot). Forums like this are where the combined experience of many can be shared is such a great benefit to all.

 

Thanks for all the advice and tech stuff, I'll pass it on to pillock who fnuked his Kwakazowi. I'm going to have a crack at shifting it with some 8" Stilsons and a hot air gun tomorrow and if that won't shift it, it'll either be Black and Decker and Easi-out time, or, he can pay our local bike 'techsperts' who'll definitely get it out, one way or t'other.

 

Yep stainless on stainless can be a real bugger if you don't use any ASP and it galls, I remember it well from very bitter experience as a very green apprentice. Some (far too many years later) had a similar experience caused by a graduate mech eng who 'knew better', him having a degree. Lesson learned a couple hours of sweat and swearing later after I made him sort out the mess he created with his degree education (I have the same degree plus many years with a PHd in Common Sense & Experience). I have also come across galling in alloys though it's not that common. In this case someone used a machine screw with a badly formed thread that re-cut the thread in the bore on it's way in, (effectively cross threading), when we got it apart the alloy section was well and truly fnuked.