Ever have one of those complete panic moments in the garage? Just got past one and can breathe a sigh of relief. Was tapping out the exhaust manifold bolt holes to clean up the threads, and you guessed it, broken tap! I couldnt fit the tap handle in there, so I had switched to a socket to turn the tap. Yes I know better and was going back and forth, but I must have been turning it too fast and didnt have any real tension feel using the ratchet. Tap snapped off just about flush, and I just about dropped the tools, fell to my knees and screamed at the sky but I didnt.
I was however in a "controlled" panic mode, knowing if I didnt get the tap out it was going to lead to much more work. There was a sliver of tap sticking out of the hole, so tried using a punch to shock the tap into rotating back out, but no luck. Then I realized I could try to remove it the same way I remove broken bolts, by welding a nut on the end. Since the tap was 3/8" I held a 3/8" nut with vice grips over the tap, hooked the welder ground to the vice grips, and cranked up the mig to max power.
It took two attempts (first try started moving the tap and then broke off the end that was sticking out) but the second, with the tap broken off flush, did the trick. Something to keep in mind if you ever break off a tap, because I consider that one of the worst things that can happen. At least with a broken bolt you can drill it out, no chance with a tap. After I got it out I used a smaller tap handle and tapped it out by hand, all good to go.

Sorry no pics, camera does not come into play when in panic mode!

 

nice save.

 

Clever save! I've been in that spot before. Your title Panic in the garage fooled me though.... Though you walked into the garage to find a Chevy parked there.

 

My garage is quite politically correct, got Ford, Pontiac, Cadillac, Buick, and yes even Chevy!
Jags have to sleep outside though, no illegal aliens allowed inside.

 

Taps love oil.
Were you using any?

 

That's where, wisdom, formed by years of experience, allows you to think instead of panic, which usually (or in my case always) only makes things worse. Very nice move on your part. Ill try and remember it the next time I find myself in a similar predicament.

 

Wanna move next door to me? When I'm working on projects I need some cool, calm, collected panic guardians as near as possible.

If it were me I would have hurled some real bad words up at the sky to the point where dogs would bark and birds wouldn't sing in the neighborhood for a week.


Tom

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Good save! I have a couple times been able to get out a broken tap by cutting a couple lengths of hardened "piano wire" or even a couple of small allen head cap screws (with larger taps) that were of a diameter to just slip into the tap flutes and protrude out of the hole enough to clamp a pair of vise grips onto the two ends and turn the whole thing. Kinda resembled a set of fangs or a long spanner wrench. I use a cutting oil call Tap Magic that works really well. I used some tiny taps on occasion in my jewelry making work.
When doing the weld method it's best to give it plenty of time to cool completely before attempting to turn it out, the welding heat can cause the tap to expand more than the surrounding piece locking it even tighter until it cools. The heating and cooling can also help to loosen it.

 

You guys crack me up, believe me I wanted to throw something, but I was more worried about having to take the truck back apart to pull the engine back out.
I dont know about years of wisdom Jim but we certainly have years of learning what NOT to do LOL.
Tom if you lived next to me at least I would know when to stop over, as long as the tools you threw didnt go through my window
No oil on the tap, will try that next time, I do use anti-sieze on them but usually only when tapping into something while trying to catch the shavings.
No way to get anything between the flutes on this one, at least nothing that would be strong enough to turn the wedged tap. Before I welded on the nut I was thinking if I could weld some steel pins to a nut to fit between the flutes and then use a wrench on that. Welding the nut on was the ticket. I didnt wait for cooling, wrench was on while still hot to just wiggle it back and forth a bit and then out. When in panic mode there is no time for standing around

 

Everyone loves pictures so here is the last part of the tap that came out



Moved to the passenger side, used oil, tapped a few threads at a time and then removed the tap to blow out the hole and the tap with compressed air. All holes done without any drama. The holes were not tapped fully from the factory, but with the 1" long header bolts I am using I needed more threads. Headers bolted up.

 

Those 4 flute bottom taps are not that strong.

I would suggest using a 2 flute spiral plug tap for chasing threads first then use a bottom tap only if you need to.

Taps can seize up when using dry just like what happened here.

Flush the holes out with denatured alcohol or something and blow the holes out with air if you can.

 

When I've broken taps I use a spring punch and just start beating the heck out of it in every direction. Usually works good on smaller taps.

 

Thanks Bob,
Tried the punch deal first, but with so little of the tap sticking out it wouldnt budge. Being an exhaust manifold hole in the back near the firewall didnt help for access either, funny thing is while doing the work in my mind I was saying to myself "dont break the tap"!

I priced those two flute spiral taps, one tap costs about half of my whole tap set, so I will just try to be careful with what I have. That tap was good for at least 10 years before it let go.

 

That was what was petrifying me when I had to re-tap a thread in the engine after a stud broke off in there. We couldn't get part of the old stud out, as it left a bit of metal in there when we drilled it and had to tap a new thread whilst trying to clear out the fragments of the old stud, and was very scary. I think you did extremely well!

 

Being a machinist for the last 44 years, I've had to deal with my share of broken taps.
I keep an assortment of tap extractors on hand and they work pretty well on taps larger than 1/4" diameter. They make smaller ones too, but the fingers are not strong enough to apply much torque.




Tap extractor

I've used the welding trick too, but dealing with small parts, I TIG weld a nut to the broken tap.
On small taps or very stubborn larger taps, I have clamped the part in my Bridgeport and using the largest carbide endmill that I can, drill out the middle of the tap. That will allow the tap threads to collapse into the hole.
On very valuable parts, or when dealing with very small taps, I take the part to another machine shop in town that had an EDM (Electical Discharge Machining) machine. Same concept of using the Bridgeport, except instead of a rotating cutter, the EDM uses an electrode that will burn out the tap. He usually charges me about $50 to do this, but the worst part is having to show a fellow machinist my latest SNAFU.
Nice recovery on your "Panic Moment", and thanks for sharing. I'll add that to my bag of tricks, for sure!