OK, for Deepfrz and scoobert (and for everyone else's entertainment), here's the whole ridiculous story.
I was reinstalling my injectors on my Westerbeke W27. I've only used a torque wrench once before, and this was my first time using this one. I set the torque for half the final torque value and started snugging up the two hold down nuts by alternating a half turn each. I was using an extension due to access issues.
The wrench never clicked and I sheared off one M8 bolt. I was thunderstruck. In retrospect, I should have done some mental math on how much force I should expect, especially since it was twice the length of my normal ratchet.
I backed off the second bolt a whole turn, reduced the torque setting way down (thinking that I had missed the click somehow) and tried again on the second bolt. I was trying to diagnose whether I had a problem with the torque wrench. Even though I had backed the other bolt off, it immediately snapped off as well. In retrospect, with only one bolt in the holder, it must have been torquing the bolt longitudinally, so it snapped at the base.
At this point I had a few words with myself.
Once I was done with the words, I took the wrench to the dock and played with one of the bolts on the dock. I found that the wrench wouldn't click no matter what force I put on it. After fiddling a bit longer, it started then working consistently. It had been stored for a long time (set at zero torque), and I guess somehow it had jammed up. Seems to be working now.
So I have a bolt extractor that isn't an easy out and a 12V cordless drill. I drill into the bolt (it comes with a little left threaded drill bit side and a ribbed cone side), jammed in the cone and withdrew the bolt using the drill in reverse. Easy-peasy and I felt like a million bucks.
Second bolt was a bit behind the lifting lug and it didn't occur to me until much later to just unbolt the lug (funny story: once I did unbolt the lug and it's attached glow
plug relay, I then shorted it to the
heat exchanger, couldn't get it unstuck because it was jammed, didn't think to turn off the master switch, and melted right through one of the
heat exchanger hold-down hose clamps).
Anyways, long story short, the lug and awkward position meant that drilled a bit offset on the second bolt. Not good. I then spent a couple hours trying to get the bolt out. I used a dremel to cut a bit of a slot and tried a screw driver but just sheared away the bit of metal on the thin side of the bolt. I borrowed a neighbour's easy outs, I drilled deeper and deeper.
By the time I was done, I had a deep hole that seems to start off to one side and then slant towards the threads from there. I'm pretty sure that I've either mangled the threads or whatever I do next certainly will. There may be a bit of drill bit stuck in there too for good measure. I'm not sure.
I never tried heat because of the
electrical bits nearby (which are now moved out of the way, but I'm now a bit late, I think). The bolt just went in a couple days ago, so it isn't corroded in or anything.
Worst case is just need to drill it out and use a helicoil. There's plenty of meat there for it. However, the bolt hole is at about a 15-20 degree angle, and I don't trust my ability to do this
work without a drill press. So I could do it myself, but I'd need to pull the
head off and borrow a drill press somewhere.
I'm thinking that a decent mechanic may have the finesse to fix this without a helicoil, or even to drill it out and insert the helicoil in place. I also may learn a thing or two from him or her.
Part of it is that I've just botched a pretty easy job and now I have a delicate job on my hands. Not sure I should keep going!!