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View Full Version : how to get a tap out brook off



Brett Hurt
05-06-2012, 10:09 PM
I have a 1/4 -20 tap brook off in stainless that is 3/4 thick, so how do I get it out Brett

Jaakko Fagerlund
05-06-2012, 10:15 PM
With an EDM.

Brett Hurt
05-06-2012, 10:25 PM
I do not have a edm Brett

darryl
05-06-2012, 10:47 PM
Speak very, very kindly to it, and offer it a hole in some very expensive metal :)

On a more serious note, I think you can dissolve it out- seems to me someone posted about that some months ago.

I broke a tap today- not really torquing on it at the time, but had been previously. All I could do was knock off the sharp end that was sticking up and leave it like that. Three out of four bolts will hold-

The best stuff I've found to make tapping easier, in all metals, is AnchorLube G771. I like that it doesn't run all over the place, doesn't smell, and it works.

hornluv
05-06-2012, 10:55 PM
Is it a through hole? If so, you can break it apart with a punch and some patience. Hit it hard and try to shatter it, then pick out what you can and repeat the process until the tap is out. You'll probably want to chase the threads afterward with a fresh tap. This will probably work ok with a blind hole too, but the pieces will be harder to remove.

Dale Lusby
05-06-2012, 11:01 PM
Is the part expensive you are working on. Could remake it. Stinks but always an option. I've never tried but what about a carbide drill.

Might find a shop that has edm. I bought a nice tap burner which is basically an edm drill press that can burn them out. You could also post location and perhaps someone could help direct you.

Boostinjdm
05-06-2012, 11:04 PM
I'd first try to weld a nut to it. If it's a through hole and that didn't work, I'd blow it out with the torch.

KiddZimaHater
05-06-2012, 11:24 PM
Left handed drills work great to remove taps. Or as stated before, shatter it with a punch or weld a nut onto it if possible.

dp
05-06-2012, 11:50 PM
If you have the time, patience, and a fondness for DIY, http://modelenginenews.org/meng/edm/index.html

Otherwise, a Walton tap extractor might work:

http://www.waltontools.com/products/extract-machsc-hand.htm

macona
05-07-2012, 12:06 AM
For aluminum you can boil the part in a solution of Alum and it will dissolve the tap out over time. Don't know if it will attack the stainless or not.

darryl
05-07-2012, 12:40 AM
Just remembered I broke a tap in an arbor that I had lots of time into already. Not wanting to remake it, I figured I'd try to grind it out. Same size tap- 1/4-20. I had a ball nose diamond tool for the dremel, so I went at it. Took a couple of hours, but between grinding at it and punching at it with a concrete nail, I managed to break it up enough to get it all out. Blind hole too. I must have sharpened that nail about 20 times- tried grinding a sharp tip on it, a tapered flat blade tip, a flat topped tip.

I think between all of it, the remains of the tap couldn't take it and finally crumbled.

One thing I learned from that- don't use crap taps. That was a Hanson- I thought it would have been ok, but a Yamawa beat it hands down. There were two major differences, the Yamawa made a slightly smaller 'footprint' in the hole, so bolts weren't sloppy, and it had a much easier action.

I did finally kill that tap though, and replaced it with the Hanson as that's all I could get at the time. In the meantime I got a power tap, and that thing has been good. Just a few days ago I was at a supplier and bought a few taps just for stock. I used the 1/4-20, and it feels like it's worn out right from the start. Another piece of crap-

Fasttrack
05-07-2012, 01:17 AM
It's in SS so you can blow it out with a torch if you are very careful and use a small tip. The SS will burn like ordinary steel. You can make a little dam out of wet clay around the hole (or wet rags, if you prefer) to keep the SS cool. Then carefully apply heat to just the tap. Once it's ready, just give it a small "precise" burst of the oxygen to burn out the tap. Don't overdo it with the oxygen or you'll start to oxidize the SS. You'll still have to clean out the threads with another tap, but it should be ok. Just use a high quality tap.

oldtiffie
05-07-2012, 05:53 AM
I shouldn't think that heat of any sort will improve the machineability of what ever grade of stainless steel the job is.

If the OP gets the tap out he perhaps has to finish tapping that hole or perhaps other holes yet to be tapped. It won't help any of completed or intended machine work either.

I am interested to know why the OP was tapping 3/4" deep when the effective length of a 1/4" diameter screw is only about 1/4". A clearance hole for the rest would suffice

If the tapping drill was nor sharp enough it could have work-hardened at least part of the hole which would increase the probabilty of the tap breaking.

A blunt or incorrect tap would not have helped much either.

http://i200.photobucket.com/albums/aa294/oldtiffie/Black_book/Black_book2_P20-21_1.jpg

JEZX
05-07-2012, 05:56 AM
sulfuic acid will eat some of the stainless , but should eat the tap alot faster . aluminum is great for that .

SGW
05-07-2012, 07:07 AM
If the job will allow a patch, you can cut out a plug containing the tap using a core drill, then bore the hole to tapping size for a threaded plug and tap -- maybe 5/8-18. Make a plug of the same stainless and thread so it's a close fit in the hole, and install with Loctite 609. As long as the part doesn't get hot the plug will never, ever, come out. After installation, drill and tap the plug for your 1/4-20.

John Stevenson
05-07-2012, 07:16 AM
I am interested to know why the OP was tapping 3/4" deep when the effective length of a 1/4" diameter screw is only about 1/4". A clearance hole for the rest would suffice



I have a 6" thick steel plate here with some M6 holes in it. Doesn't meant to say they are tapped all the way thru.

vpt
05-07-2012, 08:33 AM
I'd weld over the tap and hole and make a new hole just to the right of it. :D

Brett Hurt
05-07-2012, 08:44 AM
I well punch it out with a punch, and see how it goes Brett well let you know if it works thanks

Clevelander
05-07-2012, 09:41 AM
The value of the part will likely dictate whether is makes economic sense but you do have some choices.

They actually make tap remover tools. If the tap snapped from flexing rather than grabbing it might be a workable choice. The tool has hardened wires that fit down into the relief cuts in the tap.

Second choice: you can buy a solid carbide drill bit. A good quality one will actually drill through a tap.

A third somewhat ugly choice is to drive the tap straight back from the side you inserted it. It shears the thread where the tap is but the hole can be retapped and the reduction of thread engagement is typically irrelevant.

rustygreen
05-07-2012, 11:18 AM
I've had good luck with the 4-facet carbide tap removal drills:

http://www.mcmaster.com/#tap-removers/=hfkfa9

(bottom of the page)

These are also great for drilling out tough fasteners. You run them extremely fast, drill through slowly then pick out the remainders. Careful, they make the tap into wicked sharp little HSS splinters.

Ryan

RWO
05-07-2012, 11:40 AM
+1 on the carbide tap removal drills. They work if you have a vertical mill or a good drill press. The key is a rigid set-up and getting the drill started in the center of the tap stub.

They are made by Omegadrill and are sold by MSC as well as Mcmaster.

http://www.omegadrill.com/

As for shattering a tap with a punch, the has worked for me with a carbon steel tap, but has never worked with a HSS tap.

RWO

Horst
05-07-2012, 02:13 PM
+1 on the carbide tap removal drills. They work if you have a vertical mill or a good drill press. The key is a rigid set-up and getting the drill started in the center of the tap stub.

They are made by Omegadrill and are sold by MSC as well as Mcmaster.

http://www.omegadrill.com/

As for shattering a tap with a punch, the has worked for me with a carbon steel tap, but has never worked with a HSS tap.

RWO
+2 on this method. The 4-facet drills work great.

Bob Fisher
05-07-2012, 03:23 PM
I have had good results with a carbide end mill, of course, you need a mill for that approach. I removed an 8-32 from an expensive casting, cost me an end mill, but it worked. Double ended end mill for that matter. Bob.

oxford
05-07-2012, 05:01 PM
I have also learned that if you do smash it out with a punch and then re-run a new tap through it to clean it up, throw that tap out when you are done. Any little piece of the old tap that you hit with the new one will dull the new tap. For me it is just worth throwing it out.

Toolguy
05-07-2012, 05:18 PM
I drill taps out with a regular carbide spade drill. They are very similar to the Omega drill, but way cheaper. As stated before, it's important to have a rigid setup and spindle and be on center with the hole. If you're doing the holes on a mill, you will already be on center or be able to dial back to that location.

jimsehr
05-07-2012, 05:58 PM
I had a EDM brokentap removal service for 20 years in Downey Ca.
I think your best way is to call auto machine shops in Bakersfield and ask them who they use. I have fixed tons of parts with broken taps and bolts in them.
jimsehr

toolmaker76
05-07-2012, 06:59 PM
Probably the most elegant way to do it (without having access to an EDM) is to use a rigid set up (mill) and use a carbide spade drill. About a 5/32 diameter SHOULD be sufficient to separate the web of the tap if you get the hole on center- I have also used a 3/16" diameter bit, which basically leaves just the threads, you will have to pick them out with a scribe or similar tool. Be patient and gentle as you are going in with the drill, stopping frequently to blow out the chips (you don't want to snag your bit).

A phosphoric acid solution should dissolve the tap over a period of 3-4 days, with very little damage to the stainless steel. Diet Coke is a good source! When I worked in EDM, we used a diluted solution of phosphoric acid to clean our stainless holding fixtures. If we broke a screw off in one, the easiest fix was to leave it in the solution for a couple days, it would dissolve.

Rough and dirty fix is to find a punch you don't like (I like the idea of a concrete nail) and just start beating on it, try to pick out the pieces as they shatter. Done that quite a few times over the years! Takes a lot of patience (and be sure to wear safety glasses)!

firbikrhd1
05-07-2012, 07:38 PM
Depending on your situation you may be able to use a small punch and slowly tap on the flutes in a direction that would be consistent with unscrewing. Continue until the tap is far enough above the surface that you can grab it with pliers. This has worked for me before when the tap was broken off just below the surface.

asallwey
05-07-2012, 08:35 PM
For aluminum you can boil the part in a solution of Alum and it will dissolve the tap out over time. Don't know if it will attack the stainless or not.

I bought a bag of Alum and tried it. I heated the part & solution to around 125F and kept it there for hours. No change. Left it in for 2 days, no change. This was a tap in steel. Be interested if anyone ever had good results with Alum.

Alex

Void
05-07-2012, 08:50 PM
I bought a bag of Alum and tried it. I heated the part & solution to around 125F and kept it there for hours. No change. Left it in for 2 days, no change. This was a tap in steel. Be interested if anyone ever had good results with Alum.


Alex,

I broke a steel tap in aluminum (HSS spiral flute #6-32) and I did the Aluminum Sulfate (aka Alum) trick. It was a supersaturated solution... just simmering and no more Alum would dissolve in it. It started working very slowly immediately. Let it simmer for a couple of hours. Then went home for the weekend. Came back on Monday and no more broken tap.

Again the part metal was aluminum (6061-T6) and the tap was HSS steel.

I doubt it would work with a steel tap in a steel part. For that you would need physical tricks. Burning, breaking, EDMing, carbide drilling, tap-extractoring... or whatever.

-DU-

_Paul_
05-08-2012, 03:54 AM
If there is any tap left sticking out find a nut bigger than the tap and big enough to MIG/MAG weld through, start/play the wire on the broken tap and fill up the threads in the nut with weld. While its still red hot unscrew.

It can also work if the tap is slightly recessed but you have to be very careful you don't weld to the metal you're tapping.

Good luck

Paul