Broken Taps

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my2cents
Posts: 52
Joined: Thu Mar 25, 2021 8:56 am

Broken Taps

Post by my2cents »

I just broke a tap in a brass casting and looking for recommendations to get it out. I thought I read on the forum here of an acid that would eat the tap away with out attacking the brass, but I can not find the thread. It is a through hole and the tap size is 8-32. Any help would be greatly appreciated !
Ironflyer
Posts: 153
Joined: Sun Feb 07, 2010 2:34 pm
Location: foothills of the Berkshires

Re: Broken Taps

Post by Ironflyer »

I recently broke one in the last hole in a complicated hard aluminum part. Not a worry. There are some videos on YouTube too that’ll get you in the ballpark.
I think you’re all set being in brass, not steel out of steel though with this trick.
I took my firebricks and made a fireplace, clean of oil part with the broken tap in it in a Pyrex glass wherever fits. I set the glass vessel on a 1/4” steel plate with the fire beneath.
Water up over the offending area.
Get from the supermarket in the spice aisle a pickling spice called Alum. I dumped the little oz or two of it in the water with the part. You need to keep the water at just about a simmer. It took a few hours and a can or two of Sterno. It was a blind hole. Once the bubbles stopped streaming from the tap piece in the hole-it was gone…and I finished the tapping with a new tap. Get an idea on the plan of attack from the videos maybe- but, it’s that easy.
The Alum costs three bucks and there’s always plenty to work on in the meantime ;)
All the Best,
Paul
Last edited by Ironflyer on Mon Feb 20, 2023 10:03 pm, edited 1 time in total.
STRR
Posts: 469
Joined: Thu May 24, 2007 9:01 pm
Location: Westminster, CO

Re: Broken Taps

Post by STRR »

Tap Extractor. They come in sets and are also sold separately by size. Go slow and easy. Work both out and in a little at a time. Use plenty of cutting oil. If you break the fingers, you can purchase new fingers. The extractors come in 3 and 4 flute types but you can not use them interchangeably. Faster than Alum. I have had pretty good luck with the extractors.
https://www.aircraftspruce.com/catalog/ ... ractor.php This is a 6 pc set and is the type I have and use.

https://www.amazon.com/Samfox-Extractor ... 7231&psc=1 This type is a newer design and I have not used any of these. This type will allow you to insert to a limited depth and appears to be stronger where it counts: The fingers. Whereas the other type will allow depth to equal the length of the fingers or to the bottom of the tap but the fingers are more delicate.

I recommend purchasing ONE extractor of the size you require.

Good Luck,
FKreider
Posts: 338
Joined: Fri Feb 02, 2018 8:44 pm
Location: Massachusetts

Re: Broken Taps

Post by FKreider »

Walton Tap Extractors have been around for 100+ years. That said my experience with them has been very hit or miss, some machinists think they are a bit of a gimmick.

https://www.waltontools.com/products/extractr.htm

I've purchased a couple individually from McMaster-Carr:

https://www.mcmaster.com/products/tap-extractors/
-Frank K.
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ALCOSTEAM
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Location: illinois

Re: Broken Taps

Post by ALCOSTEAM »

or find someone with a tap eroding machine, they are basically an edm machine and many are now portable.

Look at youtube there are plenty of home made setups as well.
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Bill Shields
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Re: Broken Taps

Post by Bill Shields »

Get some clay and make a dam around it.

Dab in some sulfuric acid or vinegar with a dash of salt..use an eye dropper.

As soon as the liquid starts to run out the bottom ..
plug it. Plumber putty will work.

Wait

Pick at it periodically with a dental pick. Dab in fresh acid / vinegar periodically. Allow to drain to get fresh acid in.

It will eventually dissolve.
Too many things going on to bother listing them.
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Harold_V
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Location: Onalaska, WA USA

Re: Broken Taps

Post by Harold_V »

Bill Shields wrote: Mon Feb 20, 2023 9:21 pm Get some clay and make a dam around it.

Dab in some sulfuric acid or vinegar with a dash of salt..use an eye dropper.
My experience in refining precious metals dictates that that that would be a disaster. Brass is composed of a high percentage of zinc, which will readily be dissolved from the alloy, leaving behind a honeycomb of copper with little to no strength. You can see that happen almost immediately as the yellow color of the brass quickly turns red.

Nothing quite like an Elox (edm made for tap removal) but alum might just be the smartest approach for the average guy.

H
Wise people talk because they have something to say. Fools talk because they have to say something.
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Dick_Morris
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Re: Broken Taps

Post by Dick_Morris »

I've been able to remove a tap with a carbide dental burr in the mill. At least 8-32 is a lot easier than #2 or #3.
Sandiapaul
Posts: 567
Joined: Wed Jan 07, 2004 8:04 am
Location: Princeton, NJ

Re: Broken Taps

Post by Sandiapaul »

I've been using these things for years. They work great. In fact I used one at work yesterday.

https://www.penntoolco.com/omega-drill- ... al-drills/
steamingdon
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Joined: Sun Feb 22, 2009 9:21 pm
Location: massachusetts,usa

Re: Broken Taps

Post by steamingdon »

Solid carbide ball endmill, Bring table up on miller will machine it right out. # 8 -32 is huge. Have used this method on as small as 2-56.
steamer
hoppercar
Posts: 616
Joined: Sun Jul 22, 2018 4:09 pm

Re: Broken Taps

Post by hoppercar »

Carbide ball endmill is the best solution I have found after years working in the machine shop...if you have a ball endmill that is just slightly larger in diameter, than the diameter of the bottom of the tap flutes......you'll end up with little pieces, that u just pick out of your threads, that look like little hair combs...but be sure your endmill is not larger that your tap drill size
apm
Posts: 391
Joined: Sun Jan 05, 2003 12:21 am

Re: Broken Taps

Post by apm »

Years back when I had no kids and a lot more free time I thought a flat rate tap removal business would be a cool model. Idea being that the customer ships you part and a return label you burn it out with an EDM tap burner and ship back for a fee. It seemed like quite the little niche side gig. Is there anyone doing this. There's a lot off parts I would happily pay $50 for a tap to be removed over the years.
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