what would you do?

i snapped a tap deep in the middle of a screw hole. Its in there for good so with the remaining space to screw a short stubby bolt in how can i?

j.b weld? make a bolt

 

is there like an insert that has threads and i can use..

 

How deep in there is it? if you still have 3 or 4+ useable threads, and it's not a super high stress bolt, I would hack down the bolt and go ahead and just use what's left of the bolt.

The alternative for me would be to drill the tap with a super strong drill bit, and extract it (If possible). But since it's a tap, and it's probably in there, after 20 minutes I'd probably give up on an extrication and use what's left of the hole.

 

Doesn't the tap have flutes so you can get on either side and back it out?

Otherwise depends on what hole it is as how to fix. It can be drilled out with the right tools or removed by EDM. Don't sacrifice safety if that will be an issue.

 

often when a tap snaps off at work, we have good luck using a STRONG punch and hammer, and smashing the tap into pieces and pulling it out that way.

 

Zookie great idea - I didn't realize they were that brittle.

 

If it's that deep, I doubt you could get any progress with a puch and hammer.

I've heard of machine shops using a ultrasonic tool to break the tap into pieces, but never seen one work.

I've always been lucky enough to have a tiny bit sticking out and been able to get a needle-nose pliers in the flutes to turn it out.

One thing I have wanted to try (just haven't had a broken tap for a LONG time). Take the broken end and grind it square, thread it back into the hole and against the broken piece and slip some hardened wire down the flutes then try to back it out. It often times doesn't take much torque to back it out, you just can't get a hold of it.

Doubt it will work, but won't cost anything to try.
If you do have enough thread to possibly hold the load, you can also screw a stud into the hole with some good quality "quick metal" locktight type stuff and then us a nut to tighten the piece. It really depends on where, what, and how hot it might be.

good luck

 

Great idea.

 

Tyler, they make extraction tools for broken taps. See if you can find one. Like has been said, they fit in the flutes of the tap. If that doesn't work, try to get hold of a left hand drill bit. You are probably gonna fubar the threads, but you were gonna tap it out anyway. Might just have to go to a bigger bolt or use a heli-coil when you are finished.

Also, for future reference, threading oil is a Godsend!! I always use the stuff when tapping holes. And always back the tap up after 2 full turns. Keeps the flutes clean and gives cleaner threads.
HTH

 

Ditto what Alkasmeltzer said, broken tap extractors are a very rare bird but they are still around (I had a set I think I gave away years ago, stupid me).

 

taps are either cobalt steel or carbon steel, either case they are harder than most drills unless you have specialist drills (read expensive), and the drill will tend to push off into the softer material of whatever you were tapping , so drilling is not an option. the most likely to be successful is breaking it up, but if it is stuck in aluminium you will just knock the tap thru. i would go with the stud and chemical metal. for tapping aluminium i would recomend paraffin or kerosene, and for steel cutting oil or cutting grease.