removing exhaust bolts

[yorkie_chris]

Yeah if it will grip it, might be pushing it with only 5mm to get hold of though. Worth a try.

Milling machines make brilliant drills, overkill, what's that?

When starting drilling out a bolt or something, grind it flat, carefully find center and punch it. Drill pilot at say 3mm then go in with a drill the same as the minor diameter of the thread. Then you can pick the remnants of the thread out like it was a crap helicoil.

I am not sure you will do much better with a mill/drill press than by hand drill, depends how good you are at setting the angle up. It is 100% all about the quality of the setup. Again you'd want to grind it flat and get a nice accurate punch mark.

I once drilled 4 M12 locking wheels studs froma vauxhall astra cos id lost the removal key.
I drilled all 4 perfect and the coils just fell out, the engineers at the place i was working at the time couldnt believe id done it with a pistol drill.
Done exactly like Chris said, pilot drill first then worked way up.

Btw some studs get rediculously hard, ive got a honda 125cc engine with a broken exhaust stud, like it when i got it, tried drilling it, got about 5mm then it got stupid, used my bestest drills (tin coated jobbies, not cheap ones either), would hardly touch it.
May have to get my mate to spark erode it out.
Or cope with one stud, it is only for a go kart after all.

Originally Posted by yorkie_chris

Yeah if it will grip it, might be pushing it with only 5mm to get hold of though. Worth a try.

Milling machines make brilliant drills, overkill, what's that?

When starting drilling out a bolt or something, grind it flat, carefully find center and punch it. Drill pilot at say 3mm then go in with a drill the same as the minor diameter of the thread. Then you can pick the remnants of the thread out like it was a crap helicoil.

I am not sure you will do much better with a mill/drill press than by hand drill, depends how good you are at setting the angle up. It is 100% all about the quality of the setup. Again you'd want to grind it flat and get a nice accurate punch mark.

lol, will get some one to help me if it comes down to drilling it

will try that tool then

if not will try the slot screwdriver and nut thing

then if not i will chop and grind it flat and drill it

Originally Posted by specialone

I once drilled 4 M12 locking wheels studs froma vauxhall astra cos id lost the removal key.
I drilled all 4 perfect and the coils just fell out, the engineers at the place i was working at the time couldnt believe id done it with a pistol drill.
Done exactly like Chris said, pilot drill first then worked way up.

Btw some studs get rediculously hard, ive got a honda 125cc engine with a broken exhaust stud, like it when i got it, tried drilling it, got about 5mm then it got stupid, used my bestest drills (tin coated jobbies, not cheap ones either), would hardly touch it.
May have to get my mate to spark erode it out.
Or cope with one stud, it is only for a go kart after all.

LOL, cart should be ok with one as long as it seals properly

[mikerj]

MIG welding a nut to the exposed part of the stud has almost always worked for me, you get a fresh hex to turn and the thermal shock of the welding is effective in breaking the rust bond. You do need a reasonable amount of stud exposed for this to work though.

should i use titanium bolts as a replacement

seeing as i have 5mm of stud should i slot it and put a nut over it and try and get it out that way, or try the stud extractor EG the one posted some where above (the grip type)

im tempted to just try and slot it and but the bolt over it and get the wrench on it and see what i can do

i have heated and cooled it a fair bit and sprayed it with penetrating oil

[yorkie_chris]

Why do you want to slot it? You've no chance of turning it with a screwdriver.

I had this prob with my RD350 and a snapped cylinder dowl I tried wheld and cutting a slot but in the end it was heat + WD40 + molegrips that worked.
make sure it's hot and there is plenty of thin oil.
Chris didn't you just dremel Dizzys and drill em out without effecting the original taps?

Originally Posted by yorkie_chris

Why do you want to slot it? You've no chance of turning it with a screwdriver.

i have a ratchet flat blade screwdriver attachment ?

Ok give that a go and then you'll see why!