Help Drilling out a broken thread tap?
Had a 1/4 / 20 tap break off today in a steel door frame.
Broke inside the frame itself, (between the frame and backer plate)
left a jagged edge that I can barely see and cannot get a drill bit to get a bite into.
Any suggestions?
Best drill bit material?
They can’t get your Goat if you don’t tell them where it is hidden.
Replies
You will not drill out a tap as they are high speed steel. Sure carbide is harder but it ain't going to happen.
You can strike it with a center punch and it will most likely break or you can spend some time with a die grinder and remove it that way.
.250-20NC is a tough tap to break. Was it a 2, 3 or 4 flute tap? Something was clearly wrong for the tap to break. There are broken tap removers but I've never had good luck with them. Any supply house may have them. MSC Industrial Supply or maybe Fastenal.
The repair options are many.
4 flute. I think the issue is the backer in the frame for the door closure moved as the tap was threaded in though the frame.
Cannot get to the back side of the frame as the door is already installed, siding on etc.
I tried shattering it but it is up inside the drilled hole and even if I can drive it straight through then I need to repair/rethread the hole.
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smash it through with a punch, then drill and tap a 5/16-18 thread
or if it really matters that you need 1/4-20, install a 1/4-20 heli-coil
Sounds like your installing door closers. Any chance you can just move your closer arm bracket over and still cover your bad hole?
Exactly what we are doing, and yes I just may be able to do that.
I will look at option that tomorrow. Already JB welding one frame up from a lay out error.
They can't get your Goat if you don't tell them where it is hidden.
also get a two flute tap , gun style some call them, they are way less likly to break than a 4 or 3 flute, cordless drill and a 2 flute works like magic, I have dome hundred of tapped holes all sizes this way
Thanks I will look for that style.
They can't get your Goat if you don't tell them where it is hidden.
As said, tap extractor. It has fingers that fit in the grooves of the broke tap. If ya was closer I'd hook ya up.
MSC or McMaster-Carr, both ship same day.
Got it , I have a local Fastenal I can check with in the morning. Also a really well stocked NAPA store locally.
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Gun style AKA machine tap.
3 and 4 flute taps are very weak as you have found out. Grinding the point off is a well accepted practice if you need the depth.
Machine taps leave the cuttings in mostly one long piece. 3 flutes are mostly known as bottom taps and 4 fluters are hand taps.
Hit it harder, it will shatter. WEAR GLASSES!!!
tap extractors
http://www.mcmaster.com/#2561a527/=1k98en
luck is more important than skill in the use of these.
Thanks
I found out my local NAPA can have both the 2 flute tap and the extractor for me by tomorrow evening.
They can't get your Goat if you don't tell them where it is hidden.
Two things come to mind.
I've heard of guys cutting and grinding a small 1/4" drive socket to fit around a broken tap. Then it can be backed out with a ratchet. But that would take one heck of a lot of time.
Another way is to weld something to the tap if it's close to the surface. Take a piece of metal maybe 1/4" thick. Drill a small hole in it near one end.
Then tack weld THROUGH the hole onto the broken tap. Let it cool completely (cool to the touch) before trying to back it out.
Welding was suggested by the Napa guys.
I am not a welder , don't want to try on a finished door but if I can't get it out any other way my welders will be onsite on Monday and I will ask them.
I did pick up a heli coil kit for that size bolt though, just in case.
They can't get your Goat if you don't tell them where it is hidden.
Not sure a helicoil is the correct solution. I would lean toward a riv-nut or or something similar. They are basically a pop-rivet that hat threads on the inside. You insert them with a setter that looks like a pop riveter, but has a threaded stem. When you squeeze them in they expand on the inside of the metal, leaving a threaded insert. You might want to look at using the nut-serts instead of tapping the holes. Quicker, simpler method in my mind.
Dremel tool and a solid carbide burr. I used to have them burned out of machinery with a wire EDM.
Dremel I have, not certain of the solid carbide burr , have to check , a lot of my burrs came from my father who may well have had solid carbides.
They can't get your Goat if you don't tell them where it is hidden.
You'll quickly know if it's not because it won't touch a tap. Diamond burr would be best.
Actually, a Dremel with a cutoff blade could be used to cut a notch in the tap so you could back it out with a screwdriver.
The modern conservative is engaged in one of man's oldest exercises in moral philosophy; that is, the search for a superior moral justification for selfishness. -John Kenneth Galbraith
If it's got enough sticking out I'd give that a try. But it's probably bound up and wont back out, and most of the time the tap breaks below the surface.
You can of course cut into the surface a bit with the cutoff blade, if the tap is essentially flush.
The modern conservative is engaged in one of man's oldest exercises in moral philosophy; that is, the search for a superior moral justification for selfishness. -John Kenneth Galbraith
I've also broken them out with a hammer and punch. The teeth are very hard, but brittle. Glad I don't have to mess with that stuff much anymore.
You likely do not have a portable EDM setup?
Have removed broken #4-40 from 6061-0 without damaging the existing threads with EDM.
O.K. I'll bite. What's a portable EDM setup? Is that like a henweigh?
Not likely I have one. But to be honest I would have to know whatever it is by a more recognizable identifier before declaring I don't.
They can't get your Goat if you don't tell them where it is hidden.
Success. 5/32 drift punch with a 24oz. hammer, took a few hits but the tap broke through. retapped (carefully) and ran the screw in. Thanks to All for the help.
They can't get your Goat if you don't tell them where it is hidden.
EDM = electrical discharge machining, google for details
Dang!!Do you get to play with this machine? http://en.wikipedia.org/wiki/Electrical_discharge_machiningBut in answer to your question, no, I do not have one in my tool kit.
They can't get your Goat if you don't tell them where it is hidden.
Once in a while, have never built one although PM even published diy plans for a drill press mounted EDM 10 or 12 years ago, building the feedback gap control electronics would be othe only challenge for most folks here.
Nothing though like getting to see a vacuum ion-beam welder in operation. Had one at work that would weld but jointed 18 cm thick 4340 vac steel to titanium in one pass, only trouble with welding any steel is keeping the beam from wandering due to magnetic forces on the ion beam due to stray field deflection by the steel.
Dont have an ion beam welder at home though, but may build one if I ever retire<G>
Yes, thanks a boatload. I've learned a ton today.
In a past life I installed many many closers, panics, etc while working commercial.
Never learned about the diff. in taps. Used to blame on cheap steel because I was careful (and time consuming) running it in, then out, then in .............
Certainly didn't know about bashing the busted tap in, breaking the threads on the tap.
Here's my only contribution for what it's worth. When faced with 100 doors left and right hand in a mall. Made up a reversable template for the closer-out of a truck sign magnet scrap. No more torn paper template...........
Here's A Great Place for Information, Comraderie, and a Sucker Punch.
Remodeling Contractor just outside the Glass City.
http://www.quittintime.com/
Up until this thread I didn't know a lot of this information either. From past experience I did learn that good "starter" taps make life much easier, hard to find the good ones with a lot of taper though, seems most places sell a tap that is a cross---not quite a starter , nor a bottoming tap. Last project I did these on I made a template out of masonite, clamped it in place with spring clamps, your magnetic sign idea is great!
Edit: Just remembered ....Make sure you have enough depth over the frame to get the tap all the way in. Don't Ask, I will never admit to it.
Edited 4/23/2009 3:03 pm by dovetail97128
Yeah, the magnetic sign template idea is a winner.
The modern conservative is engaged in one of man's oldest exercises in moral philosophy; that is, the search for a superior moral justification for selfishness. -John Kenneth Galbraith
Here's a hint that wouldn't have helped here but might help someone in a different situation: Was installing an motion sensing light (in Pass Christian), and somehow, on about the 4th time I put it up (always running into problems with the mounting hardware) I managed to cross-thread the central mounting screw and strip out the bracket that it ran into. Went to a hardware store and got a replacement screw, but couldn't find a matching bracket (there were fixture brackets, but the center holes were too large). And the fixture didn't provide clearance for a larger screw. When I asked the hardware guy for a tap to match the screw he said I was crazy -- the hole was stripped out.But I'd noticed that when they made the bracket they "dimpled" it where they made the problem hole. I took the bracket back to my van, laid it down on a 3-pound hand sledge (always handy to have) in the parking lot, and pounded the dimple back. This closed up the hole enough that I was able to cleanly retap it.
The modern conservative is engaged in one of man's oldest exercises in moral philosophy; that is, the search for a superior moral justification for selfishness. -John Kenneth Galbraith
Used that idea just the other day on a brass antique mortice lock part that "wouldn't take" a tap. Just enough scrunch to make it possible.
thanks.A Great Place for Information, Comraderie, and a Sucker Punch.
Remodeling Contractor just outside the Glass City.
http://www.quittintime.com/