Broken drill bit in Broken bolt. Looking for options....

subframe replacement has gone wrong....

M14 bolt broken off inside frame rail. No access to it except via destructive methods or the bottom side. Theres about two inches of bolt in there, snapped flush with the frame rail. 

I WAS drilling it out. Till i broke a bit off about an inch and a half deep. Dead center. Its a tiny bit, and efforts to drill it out, drill next to it, or enlarge an opening to grab hold have failed. 

What ideas have the hive? I have a group chat going simultaneously with this thread, so its an all hands staff meeting of wrench twirlers. Id like to get this damn thing put back together before the new year. 

i'll start with a disclaimer, that there's way more experienced and smarter people than me that are going to see this thread.
 

Is it possible to remove the metal surrounding the broken fastener?

Weld a head or piece of bolt to the broken fastener and abandon the bit? I think the shock of heat from welding a head on breaks things loose...but I have no way to prove that.

go get the acetylene and oxy setup from your dads house. Burn the center out.

Find a thick washer that has the same size ID as the broken fastener. Heat the broken fastener with a torch and then wire brush the carbon off the broken fastener. Center the washer over the broken bolt and weld the heated fastener to the washer. Take a large nut and weld it to the washer on both the ID and OD. Say a prayer and take an impact driver and begin to gently attempt to back it out. It's has worked for me better than just doing the welded nut trick because it's easier to get a fully penetrating weld onto the washer from the broken fastener.

lotusseven7 (Forum Supporter) said:

Find a thick washer that has the same size ID as the broken fastener. Heat the broken fastener with a torch and then wire brush the carbon off the broken fastener. Center the washer over the broken bolt and weld the heated fastener to the washer. Take a large nut and weld it to the washer on both the ID and OD. Say a prayer and take an impact driver and begin to gently attempt to back it out. It's has worked for me better than just doing the welded nut trick because it's easier to get a fully penetrating weld onto the washer from the broken fastener.

I like that. Now I just have to remember it next time I'm in this pickle!

I would do it exactly as lotusseven described. 
I have also seen a few people torch out broken bolts with hurting the threaded hole too much, but I've never personally attempted it. 

I had this happen on a strut for a Ford Tempo a long time ago. Same deal with broken drill in broken bolt. I didn't have the welder option. I used a hammer drill with a masonry bit. It chiseled out the broken bolt and the drill bit. Once I got it through I was able to open it up enough to get the remaining chunks of bolt out of the hole. 
It wasn't pretty and I would do the welding washer and nut deal before I did this. 

NY Nick said:

I had this happen on a strut for a Ford Tempo a long time ago. Same deal with broken drill in broken bolt. I didn't have the welder option. I used a hammer drill with a masonry bit. It chiseled out the broken bolt and the drill bit. Once I got it through I was able to open it up enough to get the remaining chunks of bolt out of the hole. 
It wasn't pretty and I would do the welding washer and nut deal before I did this. 

Masonry bit? Holy E36 M3muffins. There's one ive never thought about. How much bigger than the broken bit did you go?

Drill bits, if big enough, can be destroyed with a snap punch.  They are usually heat treated and brittle so the snap punch breaks them up.  With a tiny bit it doesn't have enough space for the shattered parts to move and fall next to the flutes.

Heating them appropriately will destroy the temper and turn them into another hunk of metal that can just be drilled.

I've used both methods successfully.  You can't use the former if you have done the latter, though.

That's a tough one. If the bolt is stuck you're unlikely to be able to slot it and use an impact screwdriver either.

I'd break out the welder, to be honest. 

The only things that will cut the high-speed steel of a drill is a carbide two flute end milk.

=~ (

Carbide bit in a Dremel tool. The only thing that had a prayer getting not a drill bit, but a hardened, broken EZ-Out (EZ-Out my ass) from the center of a broken bolt. Hogged out the steel til the threads appeared, then picked out the chunks, and tapped it.

What tools do you have at your disposal?  

Welding is great, especially with the washer trick to space the new "head" of the bolt out.    But I'd be concerned about getting out a bolt that long with it. Remember to tighten first if you go this way and slowly rock it out.

I've had luck taking a plasma cutter to the center of a stuck bolt to make a nice hole, then using a left hand drill bit.   Oxy acetylene as mentioned, but be careful of liquifying the material around it.. Of course, that goes for the Plasma too :) Neither of those are pleasant upside down.   Wear safety glasses and don't get any plasma on your hootus.

If you have a small ball end mill around, they can be pretty good at getting a nice hole started through drill bits to drill with a larger bit.   Cobalt drill bits will cut through High Speed Steel (the common type of drill bits) better, but they are more brittle, so you have to make sure you're not angling them at all.

So, tools:

Welder

Jegs cut40 plasma cutter 

Drill

Hammer drill

Impact

Dremel

Grinder

Standard norseman drillbits

Mapp gas torch

Steve: oxyacetaline is a nogo for this being in the basement and next to the gas tank. 

There is 1.75 inches of bolt up in there, and 1.5 of drill bit.

I think the weld a washerto the chunk, nut to the washer is step one. Sounds like it at least. 

Would a diamond hole saw bit work to drill around the broken bit deep enough to grab the end with needle nose pliers?  I'm not even sure if they make them for metal since they're usually for glass and ceramics but it's worth a shot and they're not too expensive.  
 

Does anyone know if they make small hole saws for drilling into metal?  
 

https://www.google.com/aclk?sa=l&ai=DChcSEwjF1qyY-JaDAxXonVoFHXncAaIYABABGgJ2dQ&gclid=EAIaIQobChMIxdasmPiWgwMV6J1aBR153AGiEAQYASABEgKca_D_BwE&sig=AOD64_2_8fkibjStGnrYCAyz2MWAuL9rvQ&ctype=46&q=&ved=0ahUKEwjZu6aY-JaDAxWlElkFHeKoAC4QqygIuBU&adurl=

Take the mapp torch and wick some candle wax into the threads before welding?

Machinist where I used to work were always using conrete bits to get broken taps out of holes. They pretty much destroyed the bits in the process, but got the job done.

YouTube has a lot to say on the subject. One that I watched that might be worth the watch.

Lotusseven7 has the right idea.  If that didn't work I'd jump straight to "cut a hole in the side of the frame, cut out the damaged nut, weld in a new one, and weld the hole back up".  I find that it usually takes less time (and frustration) than trying to save the original frame nut.

JBinMD said:

Does anyone know if they make small hole saws for drilling into metal? 

Look up annular cutters.  They're probably not deep enough to do what you're describing but they are fantastic at making clean, fast holes in metal.  These are the ones I use most:

Blair Rotabroach

If you have enough room for a die grinder (90 degree head or whatever) you could use a carbide roatry file. They will eat through HSS like butter. 


Is there enough material in the area that the subframe bolts to so that it could be drilled out and tapped to the next size up? I've had to do that many times hwen drill bits and easy-outs were broken off in stubborn bolts; cut out the offending bits and easy outs with a rotary file, then drill and re-tap the mounting boss/flange for the next size up bolts.

In reply to Dusterbd13-michael :

I don't remember how big the bit was, probably 1/4" ish. I used a 5/8" carbide tip masonry bit because that's what I had. I think it worked because it was smashing the bit as it hammered?