Archived Broken tap

[DLausche]

We are working on a Alphacowboy's truck here fixing a blown head gasket. Head is off, machined & oringed ready to go back on. While using a bottom tap on the block stud holes - you guessed it, the tap broke. Of course it is the hole at the very back of the block. It is broken ~1/4" down in the block about even with where the threads start and the tap is/was all the way in/bottomed out when it snapped. He said he is fairly sure it broke when trying to back the tap out so it for sure is in there really tight. We've tried a bunch of homemade tools to fit in the 4 slots of the tap and get a good grip on it but nothing seems to be strong enough to back it out.



Suggestions?



Thanks,

Deon

 

[Flinty]

I have taken a broken tap out of a 7. 3l block with an easy-out. I kept a drill bit sharpener close by and would drill a little with lots of cutting oil and high rpm then resharpen. Patience was the order of the day but it worked. I think a right angle drill will get into the area you're working and with a keen eye and a mirror maybe... you just might pull it off. That is the approach I would take. I would also use a dremel tool to grind a flat spot on the tap so the drill bit won't walk. This is what worked for me. Sorry about this unfortunate turn of events for you guys.

 

[Alphacowboy]

Yeah, it pretty much sucks. Its a Titanium Tap, and a cutting wheel barely scuffs it (tested it out on broken piece still in the tool)



Tried making many tools like Deon said to try and get it out. Tried a fingered deal that I cut up a socket and socket extention to go down into the "flutes" of the tap, but they either just broke or chipped off more pieces of the tap.



We'll have to try the easy out idea, I thought about it, but didnt know if there was a prayer at cutting a hole in the darn thing. Is there a very hardened diamond bit for a dremmel that might work to bore a hole in it?



Anyway, I was really looking forward to having my truck back... but now it will have to wait again, and plus its been taking up Deons garage for 2 weeks already so I feel bad about hoggin his garage!

 

[RHestand]

I had this problem a few years ago and a friend saved the day.

He came over with a kit specifically for this problem. It was an acid solution and a neutralizer.

We put a few drops of acid in the hole and let it work for 4 to 5 min. then a few drops of neutralizer.

The acid ate just enough of the metal from the block and the tap I was able to reach in with a very small pair of needle nose pliers and it came right out.

We blew out the hole, ran another tap in and out, and all was good.

Just be carefull about letting the acid work too long. It can ruin your threads by eating too much. It only has to take a small amount of metal off the threads of each surface to release the bind and it comes right out.

My friend said he bought the kit at a machine shop supply house.

It worked for me.

Good luck,Ray

 

[Skydiver]

While working maintenance at a water plant for many years I have broken off many bolts and a few taps. The answer is patience, A little ( or a lot ) heat. The acid treatment sounds good . I use a pair of curved needle nose pliers also.

Work a little then rest. If you tire out you are going to make it worse. This problem has to be dealt with and any wrong moves could be expensive.

 

[JFaughn]

Did you get it out ?
Where are you working on it , I have a tool for removing broken taps ,
I could get away from what I'm doing after 1 pm today .
I'll pm you my ph. #

 

[JOdell]

There are diamond tip cutting tools for dremels. We cut hardened steel at work with them. It might work. www.dremel.com -Jason

 

[JFaughn]

I went over there with my Walton , broken tap remover set , its stuck too bad to remove with the tap remover .
Being that its the rearmost hole & that is broken off about 1/4" below the surface & bottomed out , it will not budge , a few solid hit with a hammer & small flat punch , no slack at all .
So short of pulling block for next options , what have others done ?

 

[Butch 97 3500]

Deon,

Try a carbide double cut ball (MSC supply) close to minor dia of the threads on a angle die grinder with air cut down so it spins slow work out the center of the tap and then pick out the flutes , its a slow going but take your time as you grind blow out chip with air. an old dentail pick is also useful.

Good Luck!!!

 

[Alphacowboy]

Thanks John for giving it a go. I owe ya one for at least giving it a shot.



Talked to a friend of mine after John had left, unfortunately, and he said to try and warm the block up (not blazing hot, just slowly get it warm) and then drop a few drops of freon on the tap and then try backing it out with the tool. By super cooling the tap quickly it should shrink just enough to hopefully free it up... what ya think, think something like that would work?

 

[DLausche]

In addition to John's tap remover tools we also tried drilling with cobalt and carbide drill bits with not much luck. It definitely took the edge off the cobalt bit. The carbide bit did not loose it's cutting edge like the cobalt bit did but still it barely made a dent in the tap. The next idea we have in line is to use a tap removal tool like the one John had today along with some heat on the block. After heating the block gently, we plan on using an electronics/circuit cooler spray on the tap itself to try to cool the tap while the block retains the heat. Hopefully the thermal expansion of the block and contraction of the tap will help loosen the grip. The Walton tap extractor does get a very good grip on the tap via the flutes.



The ball double end mill looks like a good idea. I've never seen these before. Will this retain a good cutting edge better than the cobalt drill bit we tried today? That lost it's cutting edge within a minute of use. Which is a better cutting edge - carbide or cobalt? I've always associated carbide with masonry work. A few Googles appear to tell me that cobalt is harder than carbide but the carbide bit today looks much better off than the cobalt one we tried.



-Deon

 

[GHarman]

A carbide drill bit made for cutting steel is harder than a cobalt bit by a long shot. They are also very brittle as the entire cutting tool is carbide, not just the tip. (There are no brazed inserts. ) There is no room for error in side to side bending while drilling with a carbide bit. It will shatter. That being said; they might be useful for your application as well as a diamond point grinder in your dremel. A 1/8" carbide bit will fit the 1/8" collet in your dremel tool. If you can relieve the core of the tap you may be able to remove more of it with a small diamond ball end grinding bit and work toward the flutes? Just a thought? Hope this helps. GregH

 

[Alphacowboy]

looks like Nitric Acid might be the ticket. Seems it is a common used acid for this exact problem. It will dissolve Carbides quite well. What I have read is you dilute it slightly, put just a few drops in the hole, let it sit for 5-10 minutes, then you need to put a base in there to balance out the acid and stop its corrosivness. Then, clean out the hole, and try the removal tool, and it should come right out. It should eat away just enough material to loosen up the bind between the two objects too let it free. What ya'll think? And, where the hell do you get Nitric acid? My guess its on the "watched chemical list" due to the fact its used in making Nitroglycerin Also, for a base, would something as simple as Baking Soda be adequite?



Thanks guys for your help thus far, talk about a nightmare! PLEASE, if you have to tap your block, BE CAREFUL! Trust me, you dont want to be in my shoes!!! :{

 

[Simplysmn]

Maybe try welding a haystack onto the tap then weld a nut to that ?I know that works for bolts maybe just Maybe that will help ?

 

[Alphacowboy]

Maybe try welding a haystack onto the tap then weld a nut to that ?I know that works for bolts maybe just Maybe that will help ?

problem is getting anything to actually attach to the tap is the problem. The amount of heat that would be needed to actually weld to the metal of the tap would be most likely detrimental to the block.

 

[SierraRam]

I have used some liquid refrigerant like r-22 or r-134a. Use gloves and a plastig cup, catch enough liquid refrigerant in the cup and poor into the hole, this will lower the tap temp enough to shrink it, the block mass will prevent it from cooling as much as the tap. The try to back it out.

 

[JFaughn]

As mentioned above , go to a machine shop supplier , to get a small diamond abrasive , grind away the center shaft .
I would make a collar that would bolt down to help keep the die grinder from going off center .
I prefer a mechanical vs. heat or chemical , more control and affect the metallurgy less , to avoid future problems , but if all els fails that may be a last resort .

 

[Joe Mc]

I don't know that you will be able to get a couple of "drops" of freon anywhere near it as most freon's boil (turn from a liquid state to gas) at atmospheric pressure/room temps. Maybe a piece of dry ice dropped in? if you can find that. But, the principal - heat every thing up and try to cool down the stuck piece is probably your best bet. Other than that - you'll be drilling out that hole and heli-coiling it. A friend of mine used to drag (ran in the 8:90s) with a big block Chebby that had a few stud holes coiled - he was forever tearing the motor down to inspect and put back together - sometimes between rounds - and never had a problem with pulling a coiled stud. However he was only running 13-1 compression . . . unlike our engines that probable go better then 18-1. Hope the dry ice works. I've had luck with: heat everything up, then install removal device and shoot with penetraiting oil then give a sudden definite twist that usually move whatever is stuck. Remember constant increased force (trying to remove something that is stuck) usually just imbeds it better/more - when you give that "sudden" jolt it sends the signal to the surrounding metal (especially when it's a different type material than what's stuck) that "baby you need to move" and it usually does. Patience works best - several to many attempts can be required.



Thought - sending a signal - have you tried placing a drift in the hole and giving the stuck tap a "whack" to try and tell it "hey, you 'are' coming out"? That's worked for me also. Good luck - keep us posted.

 

[Alphacowboy]

ITS OUT! Got it out with the walton tap extractor! Awsome tool!



Took a A/C coolent recharge kit and cut the nozzle off the end and inserted a basketball air nozzle. Then placed the nozzel down into the flutes of the tap and held the button down for a few seconds in each flute. The R134a Coolent also contains oil, which I think was a big help as well. It got about as cold as itcould get, and then started the attempts at backing it out. I was able to move it back forward about 1/4 turn then it would hit bottom. When I went to move it back out, it would catch. My guess is in the process of trying different methods of getting it out, I mucked up the threads higher up, or when it brock, it left a mark in the threads. I kept going back and forth trying to pull a little further than the last attept. I cooled it 3 times as well. On the second attempted I snapped one of the pegs off the tool. Replaced it with the second set I had ordered with it (thank the Lord!) And went at it again, I then got to where it caught and just slowly pulled very very firmly on the walton and then it started to move! About 1/2-3/4 of a turn past where it had caught it started to move out easily. Then it was out! Threads are fine and the head stud easily threaded in like the rest of them! I want to thank my friend Jeremy for the coolent tip! Hes a CTD owner, but not a member here, dont think he likes the internet too much. But anyway, I said many a prayers, and Thank the Lord Jesus he listened and all it took from me was some patience and determination!



Here are some pics, tap that broke, extraction tool, and my coolent contraption.

 

[Extreme1]

Good Job! Thanks for the R134 tip, I'll have to remember that one.