Best way to remove broken tap

[Ziggy]

I broke off a tap trying to clean threads in a set screw hole in a "shaft razor" line cutter. The tap broke off below the hole, so there is nothing to grab with a tool like pliers or vise grips. The shaft razor is 316L stainless, whereas the tap is presumably hardened carbon steel. Any ideas for how to remove it? Try to dissolve it with sulfuric acid?

[sagablu]

A really hard thing to remove. Can you drill and tap a new hole somewhere else? Drilling hardened steel is going to be near impossible.

[billknny]

Originally Posted by Ziggy

I broke off a tap trying to clean threads in a set screw hole in a "shaft razor" line cutter. The tap broke off below the hole, so there is nothing to grab with a tool like pliers or vise grips. The shaft razor is 316L stainless, whereas the tap is presumably hardened carbon steel. Any ideas for how to remove it? Try to dissolve it with sulfuric acid?

Remove Broken Taps with Walton Tap Extractors

Those might help--depending on why it broke. If you had it well lubricated (you were using cutting oil, weren't you?) and it broke because it got out of line you might get lucky and be able to back it out.

If it broke because it galled from lack of lubrication... you have a world of hurt...

Hopefully somebody here can offer a better suggestion...

[Jammer]

How do you remove it? You don't. Read 'em and weep.


You either throw away the linecutter and replace it, or drill another hole and start over.

[Dave_S]

I found those broken tap removers can sometimes work if the tap is 10mm 3/8" size or bigger, the smaller ones the extractors don't have enough strength.

If you can take it somewhere, spark erosion will do a nice job. There are engineering companies that will do it for you.

If it is a through hole you can try to smash it through with a narrow good quality pin punch.

Heating it and cooling it can sometimes free it up a bit, not a good idea if the part is hardened.

[Ziggy]

Originally Posted by billknny

Remove Broken Taps with Walton Tap Extractors

Those might help--depending on why it broke. If you had it well lubricated (you were using cutting oil, weren't you?) and it broke because it got out of line you might get lucky and be able to back it out.

If it broke because it galled from lack of lubrication... you have a world of hurt...

That looks like it might work--thank you for the tip! Although the cost of a tap extractor set is a significant fraction of the cost of a new line cutter...

[Ziggy]

Originally Posted by Dave_S

I found those broken tap removers can sometimes work if the tap is 10mm 3/8" size or bigger, the smaller ones the extractors don't have enough strength.

If you can take it somewhere, spark erosion will do a nice job. There are engineering companies that will do it for you.

If it is a through hole you can try to smash it through with a narrow good quality pin punch.

Heating it and cooling it can sometimes free it up a bit, not a good idea if the part is hardened.

It's #10 thread, so chances are a tap extractor won't work.



Spark erosion is an interesting suggestion. Googling it, I found this link:

How-To Remove Broken Taps, or Making and Using a Basic EDM

But I think I'll try dissolving the tap with sulfuric acid.

[a64pilot]

You buy a new part that the tap broke off is what you do.
I tried everything as a kid to remove a broken tap, you ideally can try drilling it out on a drill press with a cobalt drill.
I had no luck keeping the bit in the tap myself. Wasted many an hour trying before I finally gave up, it was one of the few things that beat me.
If was a Yoke for a read end so it was easy to remove and clamp into perfect position etc on the drill press.

I learned to not break taps that day, not much is harder than a tap.

[model 10]

A Plasma Cutter works the best. Local machine/welding shops have them or maybe you need one?

[Dave_S]

Originally Posted by Ziggy

It's #10 thread, so chances are a tap extractor won't work.



Spark erosion is an interesting suggestion. Googling it, I found this link:

How-To Remove Broken Taps, or Making and Using a Basic EDM

But I think I'll try dissolving the tap with sulfuric acid.

I've never tried acid, let us know how it goes.

Originally Posted by a64pilot

I learned to not break taps that day, not much is harder than a tap.

:-), yep major PITA




.

[Terra Nova]

I have been able to remove broken 10-32 taps in stainless steel by milling them out using a 5/32" carbide end mill.

[US1Fountain]

As a toolmaker, I’ve broken my fair share of taps. Being a #10 and broken below the surface, a carbide center drill used in a mill to keep the drill centered n the hole is my method. Trying to drill it out using a hand drill will usually end up with a broken drill in the hole too. Gotta be able to control the depth of cut and keeping it straight. Most DIYrs will find any hand method of drill g a tap out will just result in the drill walking off to the side into the softer material and breaking.
Never had any luck using those tap extractors on small taps. They just bend and are ruined. Unless you can remove the part and take to a machine shop, best to look at alt repairs as mentioned already.

[Kita]

as a machinist I have had my fair share of broken taps. each one is an individual case. there is a thing that they call an EDM machine. it is basically electrical discharge Machining, they will burn throughthe tap...the tap is harder than anything else you can put through it,sometimes as previously mentioned you can get a good carbide End Mill and get the job done but it's not easy and will probably kill the End Mill and then you have even more problems but it can be done. the guy that said a plasma cutter is just way out of line there's no room for that! but if they drilled and tapped that part and then had it Harden they will be able to use an EDM to get there. Research EDM Machining and then find a local machine shop that has one and they will be able to save that part

[Handsoff]

I had a similar problem with 2 sheared bolts in a case. I took problem to 2 machine shops. They did not even try. Too hard. So I met a guy who’s a retired circus performer. He said “no problem”. He welded a bolt to the sheared bolt and wala. I s might not work in your case but maybe an approach

Good luck

[deblen]

Originally Posted by Handsoff

I had a similar problem with 2 sheared bolts in a case. I took problem to 2 machine shops. They did not even try. Too hard. So I met a guy who’s a retired circus performer. He said “no problem”. He welded a bolt to the sheared bolt and wala. I s might not work in your case but maybe an approach

Good luck

I agree with this weld approach. Works well with bolts.
Plan on re-drilling & re-tapping for a larger set screw (1/4-20) after,if original threads are buggered. / Len