Broken drill bit

[hal 1]

I've gone and got a drill bit stuck in an engine cylinder head, here's the story,
A manifold stud was stuck in the head, a large amount of release fluid was used over a week or so to no effect, next was to weld a nut to the bit that was left hoping that the heat would help to release it.
After no success I tried to drill out what was left, pilot bit went in with a bit of a struggle but went through, next bit then went and snapped in the stud !
So, is there any way I can carry on and get out what's left of it ?
Or am I better just taking off the head and taking it to a professional ?

Hal

 

[Nick67GT]

Picture would help....

 

[Kram]

The broken bit should loosen and pull out with a few good hits of something heavy. How deep is the bit and how much stickout?

Alum will disolve steel bolt but not touch aluminuim. Some videos on youtube. Wont work on the drill bit. If its a small it it will eat the surrounding steel and free the bit then eat the rest of the bolt. It does take quite a long time and is better with some heat.

 

[hal 1]

This might be a bit big, I can't drill it out from the back

 

[hal 1]

 

[Richard.]

Did it grab and snap on exit.
Did you manage to get the hole right through

 

[hal 1]

Yes, now you mention it, I wasn't pushing the drill too hard as it's not something I tend to do, I can't remember the last time I broke a drill bit, I was using Clark titanium coated, so it's not that they're very cheap.

The pilot went through, in fact I can just about see the tip of the broken bit, I've tried to tap it out as best I can but no joy

 

[p0689109]

Have you got any burrs or thin rotary grinding diamond bits?

 

[slim_boy_fat]

How much clearance is there between the casting and the block? Could you drive it right through with a BFH and a suitable drift, even if it meant taking a grinder or Dremel to it?

 

[I'm getting on a bit]

See if you can grind a slot with a dremel in the Web and unscrew it "effectively"

 

[Nick67GT]

The one option you might want to consider is spark erosion.

Not exactly cheap, but it's a precision method of removal rather than some of the other solutions that might be on offer.

How long is the bit that's snapped off?

 

[EddyP]

Doesn't look like there's room between the casting and the block to punch it out, so how about you use say an M5 bolt, cut the head off, then position it with a nut over a deep socket, put a couple of nuts locked together on the thread and then use them to basically jack the drill bit out of the hole, bracing it against the head.
If that makes sense?

 

[hal 1]

Slim, forgive my ignorance, but what is a BFH ?
I'll see what I can do with my Dremel,
Nick
The broken bit is possibly 1/2" +
I'll have to consider spark erosion, It might be the way to go

Thanks all

 

[slim_boy_fat]

BFH = Big 'so-and-so' Hammer

 

[hal 1]

Eddy, I think I know what you mean, go at it from behind ?
I'm a bit reluctant to be too heavy handed because I know that if I do then I'll damage it beyond repair, it's the sort of thing that happens to me

 

[hal 1]

Thanks slim but see above
Things break

 

[Crater Creator]

Doesn't look like there's room between the casting and the block to punch it out, so how about you use say an M5 bolt, cut the head off, then position it with a nut over a deep socket, put a couple of nuts locked together on the thread and then use them to basically jack the drill bit out of the hole, bracing it against the head.
If that makes sense?

Yeah @EddyP I think this would be my first choice as well. Having access to the back of the hole makes it a bit less of a nightmare.
Failing that, make up a drill bit guide, bolt it on using the lower intact hole, and go at it very gently with a TCT burr or small cylindrical grinding stone.
@hal 1 - I feel your pain, been there and got the t-shirt. At least it's not a cobalt drill or an easy-out.

 

[EddyP]

Eddy, I think I know what you mean, go at it from behind ?
I'm a bit reluctant to be too heavy handed because I know that if I do then I'll damage it beyond repair, it's the sort of thing that happens to me

Yeah work at it from behind and try to press it out, you're less likely to do damage that way, and if you're just using something like an M5 bolt, you'll strip the bolt before you snap that casting.
The only other option would be to try and make up a couple of prongs to go down the flutes and then try to unwind it out.

 

[hal 1]

Thanks, I'll have a Go at that tomorrow, if I can just get that bit out then I'll take it easy with some new drills
Thanks again all

Hal

 

[Powermyster]

Will you get a circlip pliers down the flutes to try unwind it?