Best method for extracting bolts with broken off heads...

Clint, I am as nervous as you about fires with an open torch. You might try a trick I frequently use when doing plumbing work on existing pipes. Get the biggest piece of sheet steel (light weight stuff like ducting or flashing is fine). Punch a hole for the broken stub and slide the sheet metal over the broken part so that it shields everything but the broken stub when you apply the flame. This heats the bolt instead of the hole, which is bass-ackwards from the more efficient heating of the hole but it does work - especially if you take a squirt bottle of water and quickly cool (quench) the bolt once you get it good and hot. Just be careful of your hands - the sheet metal will reflect the heat back at you and you can cook a hand if you don't watch it.

Tungsten carbide MIGHT drill it, a diamond bit should do it, use plenty of lube.

Arold "Al" Green proclaimed:

I always start off with a diamond drill in a dremmel. That way it's fairly easy to get it centered for the next larger drill.

An old trick used on rusty farm equipment is to drill a hole just the size of the stud in a long piece of bar stock. Then slide that hole over the bolt and weld it on. Then use the bar stock as the wrench and turn the bolt out.

i use a spring loaded center punch to get center, then i start a drill 1/8 inch just to get a good drill center started. then i switch to a reverse drill bit and 9 out of

On Thu, 28 Dec 2006 03:36:47 GMT, RoyJ wrote in rec.autos.makers.jeep+willys:

When I used to work in a welding shop, that's the way we extracted numerous broken bolts. We didn't spend time drilling out the threads or countersinking the nut to be welded onto the broken stud.

Just find a nut large enough to slip over the broken bolt and weld it on. As previously mentioned, the new nut and added heat are usually enough to free up the broken bolt.

For broken bolts with just a small nub protruding, a nut placed over it and welded on with a wire welder (which is what we always used anyway) usually worked. If the weld broke and the nut snapped off, we'd just do it again until the weld and the heat generated were sufficient to get the bolt out. Also, a number of little button welds can be applied to the nub until there is enough added surface to finally weld a nut onto it.

Looking at the photo in this situation, there should be no problem welding on a nut large enough to slip right over the broken bolt shaft.

Well, it must be time for a progress report...

First, I tried the torch, followed by an extractor. I managed to snap the extractor off in the bolt. *sigh* I think my neighbor jinxed me on that one, cuz he warned me about it.

I was able to cut off the bolt and get the remains of the extractor out, so no real harm done, anyway. I followed that up with a titanium coated bit, to try drilling it out. I think I should have used a beefier (or better) bit, as the bit busted off inside. *sigh again*

So I picked up some better and bigger bits, and went at it again tonight. First, I had to remove the front of the Jeep, so I could get my drill in there. Turns out to be pretty easy (4 bolts, hidden behind the turn signals, in case you need to know), although I'm a little nervous about getting everything lined up again (assuming I get to put it back together some time). Gives me lots more room to work, anyway.

I got the bottom bolt drilled out pretty quick, and I THINK I'll be ok with the threads. I'll have to wait and see on that one; the remains of the bolt showed just the very end threads to be touched by the drill bit.. But the top bolt is still stuck tight, and the real problem now is the broken drill bit in it is keeping me from drilling it out.

I saw someone else with a stuck tap in this same thread, and the suggestion was a carbide bit, an A/C drill, and a case of beer (or something like that). I think I'll pass on the beer (too many memories of New Year's Eve), but I'll break out my old corded drill and pick up a few more bits to try drilling it out.

Hey, at least I won ONE fight tonight. :)

Clint

Nice work on the one. You'll get the second one eventually.

Carl

You have my symapthies on the various broken drills and extractors. I have done that enough times that my current strategy is to do the "best shot" the FIRST time. I know it is tempting to to try and work at an odd angle to avoid taking out too many related parts but it is usually a false start.

good luck.

Cl> Well, it must be time for a progress report...

I am surprised no one has suggested he gets it blown out with a torch...

I know folks that swear they can blow the steel bolts out of the cast with a cutting torch without damaging the threads in the cast.

Just a though.....

Mike

If he has access to a welder I've had good luck if there is enough bolt sticking I just weld a nut on, between the heat from the weld and the nut head they come easy.

Arold "Al" Green

Cutting torch, oxy-acetylene. This falls under "expert" use of a torch. If you don't do it right, you not only damage the threads, but what gets left in the hole is a hardened mix of bolt and cast iron that is likely to break the teeth of any thread chaser you put in it.

Earle

Using an oxygen acetylene cutting torch.

The steel will catch on fire and melt before the cast iron does apparently so the high flow of gas going into the dead end hole physially blows the melted steel out of the hole.

One Jeep owner kept snapping engine mounts (I think it was because he insisted on using the hardest bolts he could get, which sheared too easy, but that's another thread) and he stated he used the torch to blow the holes clean. He also stated he normally didn't need to chase the threads with a tap.

Mike

Arold \"Al\" Green wrote:

Thanks for the info. I guess I will not try it - definitely not an expert with a torch. Al

Mike Roma>Using an oxygen acetylene cutting torch.

__ Arold "Al" Green

Only one way to learn, Al.

Carl

Two ways actually.

:)

Nah. One way. First, you do it the wrong way a few times. Then you figure out the right way.

Carl