Stuck: Broken Tap / Tap Extractor?

[dmulk]

All,

I just purchased a used corbin seat and one of the seat mounting bolt holes was stripped out. I tried a thread chaser on the problem hole and there just wasn't enough left to make any difference.

So, I worked on re-treading the 6 holes. On hole number 5, I broke the tap off . The remaining tap is firmly lodged in the hole. I tried using needle nose pliers to chase the flutes and "twist" it back out to no avail. Tried also to use a chisel and punch to "tap" it back out. Nope.

Even though the hole is not open ended, there was enough space at the bottom of the seat to push the "jammed" bits of the broken tap out of the flutes.

Anyone have any ideas how to break this sucker free?

Thanks,

<D>

[BigTom]

Dan

The short answer is no. Not that I have no experience, but that I don't know anything that works everytime:)

You might try a left handed drill bit, one that drills backwards. You can put a little pressure on the tap fragment and it will be trying to 'back' it out of the hole.

Otherwise, you about have it. Try turning, try bashing, try anything. Sometimes it works:) At least it is an open hole. I have broken them off in a bottomed hole, using a gun tap. Not so good.

Good luck, and know that I feel for you. It can be a really serious struggle...

[dmulk]

Yup.... it's been a b1tch!

I might have to sell my other corbin to pay for a set of Walton Tap Extractors.... which look promising....

There's just not enough left of the tap to "grab".....but just enough to piss you off.... hehe

<D>

[Walrus]

Dan,
I know that this will sound really wierd, and not knowing what material the tap is stuck in doesnt help, but at the machine shops that I have worked with, they will put some nitric acid into the hole. It attacks the tap and will free it up. Only problem is what type of material the tap is in. Most of the stuff we do this with is stainless steel. I have also seen them weld a metal rod to the end and then use it to get it out. I would see if there is a local machine shop in your area, and have them do it. Machinist are good at that sort of thing.

[dmilb45]

Dan,
One thing i do know is tat a tap will ruin or break a drill bit.
Don't ask me how i know this.
Hammer and a punch and then retap the sucker. Good thing it open ended.
Good Luck

[dmulk]

Gary: Yup. Know of the acid trick..the problem is exactly what you mentioned. It's not in stainless (or another metal) that is resistant to acid.

Since the tap is hardened, drill bits definitely won't work. :)

I am thinking that I can possibily drill out just the 4 flutes to open it up a little and if I can get it to twist just a bit, I should be able to just pull it out.

Grrrrr.... this just sucks....

<D>

[Herleman]

Run a few drops of penetrating oil into the hole and leave it for several hours.

Then try a cutting wheel on a dremel tool to put a screwdriver slot on the top of the tap. The very carefully try backing it out with a screwdriver. I've sometimes found that lightly tapping around the sides of the hole with a small hammer and a nail set will also help free the tap up so that the screwdriver turns it out more easily. Don't worry if the dremel leaves a small "slot" in the surrounding metal. It won't weaken it enough to matter. YOU can also heat the tap a bit with a mini torch.

When you're using the dremel, WEAR EYE PROTECTION!!!

Work slowly. Do not try to force anything.

[George]

Ouch!

Just mount the Corbin with the remaining 5 holes and forget that one.

[Mike]

Been there myself. I have used many methods to get the busted tap out.

Sounds to me like the tap is jammed in the bolt hole, like it was screwed down until it bottomed out and then jammed had busted, taps are hard and brittle and as you know snap easily.

With this in mind I doubt an extractor will do the trick.

If you have one get a long tapered drift and center it over the tap, then whack it briskly with a hammer, that may shatter it so you can pull the pieces out or cause it to shift so you can back it out with an extractor.


There is know easy answer here....maybe drill out the bolt hole and then chip around the tap, once the tap is out helicoil the bolt hole.

[jimbob]

You might try what the car thieves do to lock cykinders on anti theft devices like the steering wheel locks, freon. Just a thought

[BigBadblue]

At work where we have access to liquid nitrogen and I have seen guys chill the tap and shatter it with a center punch.

[dmulk]

Just wanted to thank you all for your suggestions. I got it out with a Walton's Tap Extractor. Amazing little tool!

Everything is re-tapped and working great!

<D>

[motomac]

Glad your ordeal is over. We had a saying in the Navy "nothing was uglier than a busted off easy-out". Maybe we should have included taps in that saying.

[George]

Dan, can ya post a pic of that extraction tool? Sounds like a good one.

[dmulk]

Sure thing. Made by Walton (Pat from 1908 *I think*).

Find all the info you need right here:

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

I broke off a 3/8in tap, about the length of first knuckle to finger tip. Was wedged in there. It had an un-even "shard" protruding from the hole. Just enough to piss you off as you could lock some vise grips on it, but they would slip every time.

I used a very small flat head screw driver to clear the flutes and then just put the tap extractor in place and carefully, but firmly, worked it back and forth until it would move 1/8in. Then I just applied everything I had and twisted it back out. It was a bit unnerving because at one point it looked like the fingers would break off the device, but they didn't and I was able to really apply and extreme amount of force...the looks are deceiving.


Pretty awesome tool. I only purchase the one that I needed from Marshels Industrial Hardware, but I will soon add a complete set to my tool chest.

It was hard not to purchase the whole set, but I am really trying to "tighten the belt" as it looks like I have a chance to become "jobless" in the near future. :(

Anyway, enjoy!

<D>

[George]

Thanks, Dan. I don't need one now, buy ya never know. ;^)

[dmulk]

No worries, George. At least you know it exists if you need it.

Cheers!

<D>

[BigBadblue]

I have tried to used that type of extractor before with very little success. I've been designing/machining/building custom R&D equipment for 25 years and have broken my fair share of taps as well helped many others deal with theirs. Most of the time a tap breaks due to excessive twisting force and which really jams/galls the broken tap in the hole, especially if there is a lack of cutting lubricant. If you have a broken tap that just got broke with side pressure and is in a non-ferrous/thin material, they probably will work fine. But if the tap gets broken by excessive twisting force deep in steel, stainless steel or cast iron you are in deep trouble and one of these will not bail you out. If the tap is wedged in a hard material the tangs are not strong enough to break the broken tap free. THE GOLDEN RULE: LOTS of of appropriate cutting oil, sharp taps and take your time. BTW - on "through" holes use 2 flute "gun" taps. They are the strongest and the "gun" feature pushes the chip out ahead of the tap and virtually eliminates jamming (aka. broken taps).

[dmulk]

Very wise advice, on all points.

If you are in a non-f, hard metal, then I have been told acid is the way to go on getting that type of tap jam out.



Thanks!

<D>



I have tried to used that type of extractor before with very little success. I've been designing/machining/building custom R&D equipment for 25 years and have broken my fair share of taps as well helped many others deal with theirs. Most of the time a tap breaks due to excessive twisting force and which really jams/galls the broken tap in the hole, especially if there is a lack of cutting lubricant. If you have a broken tap that just got broke with side pressure and is in a non-ferrous/thin material, they probably will work fine. But if the tap gets broken by excessive twisting force deep in steel, stainless steel or cast iron you are in deep trouble and one of these will not bail you out. If the tap is wedged in a hard material the tangs are not strong enough to break the broken tap free. THE GOLDEN RULE: LOTS of of appropriate cutting oil, sharp taps and take your time. BTW - on "through" holes use 2 flute "gun" taps. They are the strongest and the "gun" feature pushes the chip out ahead of the tap and virtually eliminates jamming (aka. broken taps).

[George]

Dan, read this article (http://www.superbikeplanet.com/2007/May/070517a.htm). There's a method for removing a broken easy out. ;^)

[dmulk]

George,

That was a great story. What a great read!

Thanks for that!

<D>