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Broken hex bolt removal

I don’t remember - did the bolt break when you tried to remove it? Or did you find it that way?

Either way, if the steel bolt broke when being removed from an aluminum casting it sounds like it’s pretty much fused to the aluminum, the threads will be gone, regardless of how you get it out of there.

@texases “did the bolt break when you tried to remove it?”

the hex bolt head broke off when I used a socket wrench on the otherwise in-tact pieces. the fracture is pretty much where it becomes threaded at the head end.

@texases " if the steel bolt broke when being removed from an aluminum casting … the threads will be gone"

yes, it is an aluminum alloy of some sort. I have a tap. need to learn about tapping.

another approach I thought of is to just drill a hole (eventually I hope), and put a plain bolt in there with nuts/washers at either end, with the torque for the original bolt.

I like your drill out then bolt+nut and washers idea.

I have seen small heavy duty clamp bolts that look like a small c clamp but with heavy duty threads and a hex bolt head. I don’t remember what they were called or where I saw them but I think the were being used in a muffler shop.

There’s a specialty drill bit for metal that drills a donut hole. Drills 360 degress around the extractor, but doesn’t touch it. This makes it easy to remove a stuck extractor. It comes out with the plug in the middle. Machine shops usually have these on hand, as one task a machine shop gets requests for – and probably helps them immensely in paying the bills – is help with hardened extractors which snapped off during a DIY adventure and are now stuck in the hole.

@GeorgeSanJose - yes I know what you are talking about. the fine-control needed here might be beyond my abilities, and too risky to find out the hard way.

@oldtimer11 I don’t follow -so put a c-clamp on the piece? If that’s what you mean, then I really need to get a pic of this thing on here.

other ideas: hammer drill with carbide tip. not sure if can find small enough one.

I’m done. here’s what I did:

not sure I mentioned it, but tried LH drill bits. no luck.

to recap: broke bolt extractors twice in the bolt. the last time, I used tungsten carbide cutting rotary tool bit until it wouldn’t reach in because of the angle anymore. had to get a tungsten carbide “ball” cutting bit. for some reason, craftsman doesn’t make the long cutting bit with a rounded end. anyways, had to mash that ball cutter around a long time until finally broke through the extractor chunks (the hole was otherwise through the bolt).

at that point, I could have tried another extractor, doing it even better, or drilling a clean hole for the "plain bolt’ soution. but I had an M8-1.25 tap and corresponding drill bit (17/64-inch, or 6.74688mm), sears combo set, on hand. first time ever tapping a hole. figured the next step after that if it fails is to make a clean hole.

long story short, managed to get the hole re-tapped. cleaned the other one too. worked great. unfortunately, angle is off by maybe 5 degrees on the damaged hole that is the subject of this thread. it was fun to tap!

anyways, problem solved - apparently - actually, I’ll have to report back about how the transmission mount - that’s what this piece is, basically - hangs to the car in the long run.