Drilling out a broken thread tap
- Thread starter 53 hemi
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Capt Chrysler
Well-known member
Last one I broke, it took and EDM to burn it out.
Good Luck
Capt. Chrysler
Good Luck
Capt. Chrysler
Lotek
Well-known member
You aren't going to drill a tap out, it's too hard, what's it in?
Had that problem before, ended up banging it out with a punch. Really difficult one without making it worse because usually that metal is way harder than most screw/bolts.... interested to see what you come up with... is the bit broken above the surface? Where you can get some small vice grips on it and turn it out? Post some pics to help.
EDIT: Was writing while Lotek was posting. Agree, not gonna drill it out, if you don't mind re tapping best bet is to probably punch and hammer it out or use heat like Capt did.
EDIT: Was writing while Lotek was posting. Agree, not gonna drill it out, if you don't mind re tapping best bet is to probably punch and hammer it out or use heat like Capt did.
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dieselgarage
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- Dec 18, 2012
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- 277
cgall
Well-known member
I had to do it quite often, small chisel and a hammer.
ranger302
Well-known member
Do it all the time. Solid carbide ground to a point then the cutting edge ground in half. I will try to find a link. http://www.use-enco.com/1/1/56230-od-5-64-omegadrill-solid-carbide-tap-extractor-drills.html
rlitman
Well-known member
Torch it out. It is actually pretty easy if you have an o/a torch.
dawgee
Well-known member
edm is the easiest (because you dont have to do it) depends on the size of the tap. sometimes you can break them out with a hammer and punch or if you can put what you broke it in on a drill press or milling machine then a carbide spade drill will do it
murphaayyy
Well-known member
i broke off an extractor used on an exhaust manifold bolt for a ford. what ended up working for me was drilling small holes next to the extractor to relieve pressure. one slightly bigger hole to pick it from behind. then redrill the hole bigger to fit a helicoil. before that there was an array of bits used going from masonary, carbide, diamond, every metal but full (not coated) titanium. they all showed relatively slow progress drilling in to the extractor bit at low speeds with pb. there was no way the engine was going to a machine shop too.
MotoDave
Well-known member
Weld a nut to the end of it (if accessible) is my favorite all time method. I hate breaking taps.
Professur
Well-known member
Just ... if you're going to wallop a tap, wear eye protection ... bits WILL fly ... and they will cut and slice.
skulldrinker
Well-known member
Slow 800 rpm or less is what I used to get my last one out. Used a Colbalt bit 3-4 steps until it was gone. Right hand bit since a left hand won't help on a tap.
edited Right hand bit since it won't help on an 'easy out' seems i was drilling out an easy out not a tap. Probably same difference.
edited Right hand bit since it won't help on an 'easy out' seems i was drilling out an easy out not a tap. Probably same difference.
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CaseyJoes.
Well-known member
O/A torch if it is broken off in cast iron and it is not a blind hole. Otherwise I would say EDM as well...
rlitman
Well-known member
What are you talking about? You can torch a tap out of steel just fine. Or even aluminum. Probably not brass, but who ever broke a tap in brass deserves what they get.
Cast iron has nothing to do with it. Neither does it being a blind hole or not.
CaseyJoes.
Well-known member
It is much more difficult to torch out a tap or a bolt from a blind hole than it is a hole you can simply blow the bolt/tap out the other end. Good luck torching out a steel bolt/tap/extractor out of a steel part without blowing the threads out as well. And no a torch will not cut aluminum but on common applications I have a REALLY hard time believing that it is possible to torch out a steel bolt/tap/extractor especially not on a blind hole when the melting point of aluminum is 1000 - 1500* degree lower than common steels.... Even brass has a significantly higher melting point than aluminum.
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At work we have taps break all the time, sometimes because previous shift operate wont say how many parts are on it, other times, it just happens, even on new ones.
"most' of the time, a punch and hammer are all that's needed. We take and grind down old taps since they are very hard, and use these for the punches...regular steel punch's are easily beat to **** since the tap is harder thean they are.
The few times we cant spin them back out, we have to have them burnt out, but that's a rarity since typically a punch and hammer are all that are required for most situations.
"most' of the time, a punch and hammer are all that's needed. We take and grind down old taps since they are very hard, and use these for the punches...regular steel punch's are easily beat to **** since the tap is harder thean they are.
The few times we cant spin them back out, we have to have them burnt out, but that's a rarity since typically a punch and hammer are all that are required for most situations.
rlitman
Well-known member
Have you ever actually tried this? You sound like you're completely missing the principles of how it works.
The sharp flame from a welding torch tip will easily heat a tap or bolt to red hot (the preheat temperature required to burn steel), while not overheating the surrounding metal (if you use a cutting torch to do this, you've already failed; you must heat ONLY the top of the tap, with a single point flame). This works because the tap is not in good thermally conductive contact with the surrounding metal, and the mass of the surrounding metal acts as a heat sink to keep it cooler. So long as the surrounding steel is below the point of glowing, turning up the oxygen will do nothing to it. But with the tap glowing, it will readily burn in an oxygen stream. I've done this dozens of times, and it will NOT damage the internal threads a bit (but it will leave behind some dross from the cutting that you need to clean up). You can't say the same for removing a tap with a chisel.
As for a tap buried in aluminum, remember that it takes much more heat to weld aluminum than steel, because aluminum is just so darned thermally conductive. It will soak away the heat from the area around the tap so quickly, that in aluminum, this will actually be much easier than in steel.
Brass isn't nearly as conductive, so I'm not sure if it would work. Never tried it myself.
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cyamaha2007
Well-known member
O/A torch is my go to. This week i used it to remove a tap in the crank shaft of a large gen set. Some dingle berry broke a 25mm(ish) tap off while chasing the threads. He didnt have a big enough tap handle so he used a 1/2in impact with a 12pt socket. When he bottomed the tap it broke about 1in shy of the surface. What a *****.
Buckgnarly
Well-known member
george4
Well-known member
^, small welding tip with an oxidizing flame, as soon as the tap gets red, turn off the acetylene and the tap burns out. Have not tried it with Aluminum though.
riceburner
Active member
- Joined
- Jun 8, 2007
- Messages
- 31
I will tig on the end of the broken tap if I can get at it with some low carbon steel (usually Inckonel -sp.) and with a pair of vice grips work the broken part out - works everytime.
fredybender
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- Joined
- Apr 16, 2012
- Messages
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Hard cut drill by Sandvik...
Made especially for drilling out broken taps, and its the cats meow!
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Made especially for drilling out broken taps, and its the cats meow!
cyamaha2007
Well-known member
Wow!!!....impact with tap?!?!
I know right. He definitely isnt the sharpest spoon in the drawer.
Zelatore
Well-known member
'sharpest spoon in the drawer'
I'm going to steel that one....
I'm going to steel that one....
Great topic. Thanks for asking this. I have a project car waiting for my retirement that, among it's other problems, has a tap broken off in the exhaust manifold flange.
This was tried on the tap mentioned above, and promptly sheared off right below the weld. I was assuming welding on a tool like a tap was a no-no.
Lots of interesting ideas here though. Bookmarking this one for sure.
This was tried on the tap mentioned above, and promptly sheared off right below the weld. I was assuming welding on a tool like a tap was a no-no.
Lots of interesting ideas here though. Bookmarking this one for sure.
rlitman
Well-known member
This is a great method for a bolt broken off. Not such a great method for an ez-out or a tap, but that doesn't mean it is guaranteed to fail.
Often times, a tap is broken when turning forwards. At that point, it may be easy to turn backwards. Perhaps as much as a quarter turn, before it hits the chips from the other side and has to break them off.
Knowing this, I have in one or two occasions (I will admit that this works less often than it fails) been able to use a sharp pointed punch to carefully turn a tap back out far enough to where I can get a grip on it, and then finish turning it back out. Of course if it happens to break as you're turning in reverse to break out the chips, this won't work.
So, yes, a tap is very brittle, but it also doesn't get corroded into the hole like a bolt can, and anyway, the application of heat will always free things up a little as well.
383novamike
Well-known member
My method is cutting/grinding flat,hammer and a punch and shatter it.Has never failed for me.
That is a legitimate question. EDM = Electric Discharge Machine/machining. Also called spark machining. It is not unlike a small welding rod. Basically the rod burns a hole down the center and often the broken piece shrinks in size and comes out easily afterward. When I worked for CATerpillar I had a unit that would attach onto the side of equipment (bolt on or magnet) so one could remove a broken bolt, tap, drill bit, etc ... where ever needed.
It's good to see the OP was able to remove the offending piece with cobalt bits & chisel. No need for more elaborate methods.
Speaking of ... here is a video which shows the EDM process quite nicely.
Metal Disintegrator (Tap Burner)
>>
Speaking of ... here is a video which shows the EDM process quite nicely.
Metal Disintegrator (Tap Burner)
>>
Professur
Well-known member
I really would like a good vid of the O/A method at work. Although given my phobia of acetylene I can't see myself every maning up to try it.
As long as you're not welding, there are a number of oxy-fuel alternatives. Oxy-propylene and Oxy-propane work fine for brazing and general purpose heating-stuff-up-glowing-hot, and those gases are comparatively stable and safe compared to acetylene. And propane, at least, is also a lot cheaper.
Please note that oxy-fuel rigs need a fuel hose, fuel regulator, and torch tip made specifically for alternate (non-acetylene) fuels. Everything else stays the same, though.
Back to drilling out taps. There's a big difference between carbon steel, HSS, and carbide taps. A carbon steel tap could probably be annealed with an oxy-fuel torch and drilled out without eating the drill bit too badly.
And incidentally, I recommend carbon steel taps be used only for chasing damaged threads in steel, or maybe tapping "easy" metals like aluminum and brass. Carbon steel taps **** for tapping steel, they dull after about half a hole. A HSS tap is light-years better at tapping steel and will tap dozens of holes with much less effort and therefore less chance of breaking.
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rlitman
Well-known member
Oxy-acetylene flames form a sharper cone than any other flame except perhaps oxy-hydrogen. Oxy-mapp (ok, mapp is no longer commercially available, but this was the next-best-thing when it was) has a much softer flame that would be unacceptable to burn out a tap. It is very important in this use (as in welding) to have the heat concentrated to a point, so this is one case where only oxy-acetylene will work.
Brazing torch tips are the same, no matter the fuel gas used (with one exception I can think of that isn't relevant here). They just have one hole. You add oxygen and fuel, and burn it.
Cutting tips are indeed different (but people have simple done diy modifications to use propane with oxy-acetylene cutting tips), and air-fuel tips must match the fuel being used. The fuel regulator for acetylene can indeed be used for propane in most cases. Grade T hose is suitable for all fuel gases. Other types of hoses are acetylene only.