Broken 1/2" Tap in a cylinder head bolt hole. Major Help Needed

cheap bronco

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Well I have outdone myself this time, first time breaking a tap in a hole. I figured i would chase the threads and clean them up before assembly of the heads and now Im screwed. I have tapped many holes in the past from 1/8" to huge ones, and never a issue, it has to happen on a diesel engine block. The tap broke in a cylinder bolt hole. I have drilled through it with a carbide bit and tried to use a easy out, but broke the easy out also, had to start all over. I got to the part where now I have a hole drilled in the middle of the Tap and what now. I have tried to use a 50/50 mixture of acetone and ATF, no go. I also tried using heat the best I could with a acytelene torch, no go. I also tried taking a can of freon and holding it in the hole hoping it would shrink the tap a bit, no go. Aside from taking it to a place with a EDM machine, lack of funds for that, I need serious help.
 

blown84

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maybe a left hand thread tap, bout half to three-quarters of the way down the broken tap, then a small grade 8 left hand thread bolt in it?
 

typ4

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was it a cheap tap? got a welder? Slip acopper tube down the hole, weld it full above the deck surface ,let it cool and try to unscrew it.
and keep doing it till its out, they actually make a stick rod that is designed just for thi purpose, protect all surfaces from spatter.

Also a grade 8 bolt with some slits along the threads makes a much better thread cleaner than a tap.

and if it broke when it hit bottom you are double screwed.
 

typ4

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maybe but the block holes are pretty recessed
 

redmondjp

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I've had this same thing happen, and the only thing that worked for me was to use a small-tipped chisel to break off small pieces of the tap until I got it all out. The hole was in sad condition after that, however.

I have also seen the tap removers mentioned above, but they are not common.
 

franklin2

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It's been my experience if the tap is as stuck as you describe, no type of extractor is going to be strong enough to pull it out. I applaud you on having a carbide bit and actually getting a hole drilled into the tap, that's a major feat in itself, even though it didn't work(it must be really stuck).

In a previous thread there was mention about a special welding rod for extraction. I have seen and used this myself, and it's pretty neat. I would go to a local welding supply shop, and see if they have any they could sell you.

We had a salesman come by where I work, and demonstrated these things, and we got to try them out. We actually used a regular nut, not copper. We put the nut on the end of a bolt about 1 thread, and then took this rod and stuck it down the middle of the nut and let the weld build up to the top of the nut. Let it cool, and then turn the nut and it comes right off, and you are left with this metal "nipple" that you formed with the rod sticking up, and you can turn this with vise grips to get something loose. It's pretty cool.

If you could somehow hold a 1/2 nut in place over the hole, and build it up with this special rod, I bet you could get it out. The shock of the heat will help loosen it also.
 

typ4

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the reason for the copper franklin is the threads start way down in the hole and we dont want it sticking to the block.

I was thinking if that tap drilled it couldnt be real good quality, I have never been able to drillone.
 

icanfixall

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My thoughts exactly Russ. I have used many taps over the years and never have I seen one that could be drilled. I have seen the EDM jobs and they are terrific for what they do. What towcat posted is about the best tool for getting a shuck tap out of a hole. That extracter has 4 legs that slip down into the sides of the tap. Then you just turn it out normally. The stuck tap might be able to have some heat applied to it from inside the water jackets too. Some Aerokroil is a great product for just this kind of proglem. Srray some in the hole. Heat it up to 250 to 300 degrees. Let it cool keeping the hole filled with it and it probably wil work out easily. BTW the threads are 1 inch counter bored down from the top of the block. Then the threads are 1 1/2 inch deeper til they reach the bottom of the blind drilled hole.
 

riotwarrior

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Interesting thread...dunno what to suggest all are good so far...hmmm...I'll just sit n watch for now...


:popcorn:popcorn
 

riotwarrior

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was that a pun. LOL

Seems it was...not intended though...

OK so what about taking a torch heating the tap goodnhot...let cool take out the temper etc and slowly drill it out with LH drill bits increasing in size each time.....Hmmm???/
 

alienturtle

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how he got a drill bit started is beyond me. Iv always had to just chip the tap out little by little but iv never had one stuck way down in the hole. Good luck man
 

tham

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Seems it was...not intended though...

OK so what about taking a torch heating the tap goodnhot...let cool take out the temper etc and slowly drill it out with LH drill bits increasing in size each time.....Hmmm???/

I have used LH drill bits for this also and it worked pretty well.
 

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