Removing broken bolt question - dumb question alert

[Dark_Horse]

When drilling into a broken exhaust manifold stud - how far do I have to drill into it before using a bolt extractor? I was under the impression that I needed to drill the entire way through it to allow the penetrating oil to work it's magic from both ends. Is that not the case? For some reason, I can't get the drillbits to go more than 1/8 - 1/4 inch into the studs.

 

Those studs are very hard. Normally i drill 1/4-1/2 into the stud. there has been times i had to drill the whole thing out and re-thread it.

All i can add is, best of luck and http://www.plymouthlaser.com/tbolt.htm. I had to do this on my 7cm housing, if you can, go all the way. I even took it to a little mom and pop machine shop and he handed it back to me, "it keeps breaking my drill bits, i cant do, so sorry"

Took some heavy machinery at a brewing company (will leave nameless) machine shop to get the bolt out.

If your drill bit is harder than the material you are cutting, you'll do fine. If its a cheap bit and softer than the bolt/stud, dont bother. If you are at 1/4", hammer in the extractor then give it a go.

Here is me working on a broken bolt. Softer than your stud, but same principal. http://www.youtube.com/watch?v=u8wspxPKWLA


This was also informative if you have the tools. http://www.youtube.com/watch?v=cTRUXRv2HFs

 

[Dark_Horse]

None of the cobalt bits seem to be able to drill farther into the stud than 1/4 inch. Are there bits that are harder than cobalt bits?

 

[Barnes]

Wow. Short of tungsten-carbide bits, you don't get much harder than cobalt. Maybe coated cobalt, but you should be able to get through it with a cobalt bit.

 

[broxma]

The way we do it is weld a nut onto it. Set the nut on the broken end of the stud and then TIG weld it from the inside. Smack it with a hammer one good time and turn it out. Am yet to have a failure using this method and takes about 5 minutes if the person is skilled in it.

/brox

 

[Dark_Horse]

The studs both broke off inside the head, so there is no way to weld a nut onto either of them. If they won't come out with drill/extractor method, there is no other way they'll come out. I really don't want to buy a new head...But it looks like I may have to.

 

[beaner]

Taking it to a machine shop might be your last resort.

 

[Dark_Horse]

Was able to get 1 of the broken studs out with a bolt extractor. Will have to go pickup a few more cobalt bits before I try to extract the last broken exhaust manifold stud.

 

[Rausch]

Get some heat on the bolt when you're ready to extract. Should help up the success rate.