drill a bigger hole then a bigger hole then a bigger hole till you get close to the threads. then you should be able to peel or chisel the remains into pieces that will come out.

 

ok, well here's a stupid follow up question. How deep does the snout go, or the bolt hole? Could I bottom out the drill bit into the crank snout somewhere? I don't want to keep drilling thinking I'm in the bolt and really be drilling on the crank, is that possible?

 

how much bolt did you break off, i show a 2.25 in bolt in the parts book i have. could measure the broke part if it has any of the bolt left on the head and then figure how much is left.

 

I have 3 of the same bolt type here as the one which broke off. The original bolt length including the head is 3 1/4" the broken bolt including the head is 2 1/2" so there is about 3/4" section in the snout.

 

should be a inch and a half of blank space there so you should feel when the bit gets to it.

 

I had noticed a difference when drilling earlier, I think I fully cleared/drilled through the bolt. Yet still having the troubles. I'll try and get some bigger bits and drill the hole larger I guess. Don't want to risk breaking the extractor off inside. I recently purchased a rethread kit as well, could I use the same size threads when I rethread the hole, isn't that called "chasing" the threads? learning new stuff as always here.

 

i have had to run a tap in mine to clear the threads before. so long as you dont take steel from the crank threads you can chase or retap it to the same size. i have taken a small amount from a bolt hole on a few of the bolts i have taken out this way and tapped them with no problems. some i used a stud so i did not have to take the bolt out again and risk stripping completely.

 

Went out the other day and bought a cobalt steel bolt extractor set, well the bit didn't last long at all! As mentioned previously I already have a center hole drilled through the bolt with another smaller bit. I put a slightly bigger bit from the new cobalt set to drill it bigger and in under a second the bit disintegrated into a few pieces which I managed to get out of the hole. So now I'm going to go back to autozone and figure out what I can do. Any thoughts on this? I've about lost it! Was the set I got too weak? I couldn't find any other material extractor sets at my local stores.

 

Cobalt drill bits are harder, but they are also more brittle than other high speed bits. Pick up a set of: Left Handed Drill Bits
The reverse turning, and jarring action while drilling can help to back the bolt out. I'd stick with the titanium coated bits instead of cobalt to lessen the chance of breaking off again. Next time you might not be so lucky to get it back out.

 

The set I bought is OEM Bolt Extractor set, cobalt steel with titanium coated bits. They were RH bits though not LH. Wouldn't have mattered in this case since it broke literally in under a second. I know there are different grade cobalt bits some being just for wood and the kind I supposedly had which is used for steel or alloys in bolt extraction etc. But apparently my set was weak.

I can't find any other material bits in sets that I would need at my local stores, so I guess I'll have to buy online now. As mentioned earlier in the thread, carbide bits should be my best bet for strength in this problem?