| Vikash |
I drilled and tapped 32 holes in 8 heatsinks earlier today, and snapped the tap with just 2 holes to go :mad:
The tap is M3 size, and there's nothing protruding to grip 'n turn. Any ideas how I can get this tap out without damaging the thread? |
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| jaycee |
| If you have a drill press, try and drill it out. Thats about the only thing you can do. |
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| Conrad Hoffman |
| I hate it when that happens :mad: If there is nothing protruding, you can either open up the material around the tap with a small burr in a hand grinder (MotoTool), or drill a larger hole in from the opposite side to grab it. My guess is neither of those solutions will do for you. There are shops with EDM equipment that will burn it out for you with no damage to the aluminum, but it may cost more than the heatsink is worth. People do that with really expensive stuff. Sometimes a person with a small arc welder can spot a piece of rod to the top of the tap to turn it out. There are also small tools available from machine shop suppliers that have two or three fingers that go down the flutes and allow you to turn it out, but if the tap is tight I question how successful that method will be. Sometimes tapping the top of the tap with a small flat punch and hammer will loosen it up (add some lube obviously), allowing the less damaging methods to have a chance at working. Finally, the classic method is to drill around it, remove the thing, then ream the hole to a larger size and press fit an aluminum plug in place, followed by redrilling and retapping. Whew! |
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| BWRX |
| quote: | Originally posted by jaycee
If you have a drill press, try and drill it out. Thats about the only thing you can do. |
This works well with screws, but a tap is usually made of a harder material... Screws usually crumble and fall apart if you drill them. I don't think a tap would do the same thing. Taking your work to a machine shop would be your best bet if you want to salvage it. They've usually done this sort of thing many times before. |
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| chipco3434 |
Ugly, but it works if there's a tiny bit still above the surface or if it's flush.
Use a nailset or a sharp punch. Use the punch and a small hammer to tap on the flutes to unscrew the tap. Patience. Just keep tapping on the broken tap, it will unscrew.
Next time use a two flute tap. They're stronger and less likely to bind. |
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| Peter Daniel |
| quote: | Originally posted by Vikash
The tap is M3 size, and there's nothing protruding to grip 'n turn. |
Even if it's protruding, it will break when you try to turn it. Drilling it out is out of the question, it always slips and you drill aluminum.
You may try what chipco3434 is suggesting, although I never did it myself either. When I break the tap, I almost always make a new hole.
More info here: http://www.diyaudio.com/forums/show...3799&highlight= |
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| 405man |
I broke a tap while trying to remove a broken stud from an alloy cylinder head on the car. As the taps are hardened you can not drill them out. I took it to a local firm who used a spark erosion machine to remove the broken bit. The process cut a cylindrical hole around the tap which was then removed, they said they did work for a local aero engine manufacturer and had removed many broken taps from various exotic materials
Stuart |
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| Nordic |
Damn I threw the flier away, was recent, RS components sell a broken tap remover kit thingy... Think its like taperd drillbits to prevent it getting stuck maybe call their help no?...
I would take Peter Daniel's word as fact. He is a metal master!!!!
Thanks for teaching me how to cut aluminium on my tablesaw. |
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| jacco vermeulen |
One way is to make the heatsink really hot, then very rapidly cool it off.
Aluminium has a thermal expansion ratio almost twice that of steel, but is much softer.
The threaded hole in the heatsink is molded around the expanded tap end by heating and cooling the heatsink successively. A trick my dad tought me, i'm an ex tap-remover child slave.
May terminate the anodising though, and not for cyl-heads. |
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| Vikash |
Thanks guys.
I brielfy entertained the idea of grinding a slot with the dremel to screw it out - but didn't fancy massacring the heatsinks surface.
I read about someone who glued an Allen key to the broken tap and then managed to unscrew it which I though was interesting.
But in the end, I think I've just saved myself any grief by drilling and tapping new holes 5mm higher up. |
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| Vikash |
The story: I use my drill press and manually turn the chuck to tap holes usually. But with so many threads to make I started using the drill press with a quick start stop action to tap most of the hole and finish by hand - which works superbly usually. The problem was that they were all blind holes, I didn't adjust the pulleys to the lowest torque setting as I usually do, and the killer - I didn't catch the stop button properly on that second from last hole.
The lesson: speed kills. |
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| auplater |
If you're not "affeared of it", you can dissolve a tap out of aluminum, using 40% nitric acid... quicker if you gently warm it up
won't touch the aluminum, but will dissolve the tap (might take soaking for awhile, preferably outside)... sometimes, the edges dissolve enough that the tap loosens and falls out.
I've done this many-a-time.
I also have a Sears broken tap remover, which has reverse threads... but requires a small hole drilled into the jammed tool, which ain't easy as described b4... better for softer jammed screws...
John L. |
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| Peter Daniel |
| quote: | Originally posted by Vikash
The story: I use my drill press and manually turn the chuck to tap holes usually. But with so many threads to make I started using the drill press with a quick start stop action to tap most of the hole and finish by hand - which works superbly usually. The problem was that they were all blind holes, I didn't adjust the pulleys to the lowest torque setting as I usually do, and the killer - I didn't catch the stop button properly on that second from last hole.
The lesson: speed kills. |
The easiest and most practical way to tap at home is using cordless drill: http://www.diyaudio.com/forums/show...ight=#post69413 |
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| AR2 |
| quote: | Originally posted by Vikash
The story: But with so many threads to make I started using the drill press with a quick start stop action to tap most of the hole and finish by hand - which works superbly usually.
The lesson: speed kills. |
You are a brave man.
Talking about treading, I recently invested in the new toy. Oh man, what a tool. The small treads are not an issue any more. Works like a charm. It has clutch, self feed and self reversal. All that is needed is to properly adjust the clutch and follow the feed. With all the holes we have to tread in this hobby this tool is a life saver. |
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| Zen Mod |
| quote: | Originally posted by AR2
You are a brave man.
Talking about treading, I recently invested in the new toy. Oh man, what a tool. The small treads are not an issue any more. Works like a charm. It has clutch, self feed and self reversal. All that is needed is to properly adjust the clutch and follow the feed. With all the holes we have to tread in this hobby this tool is a life saver. |
Bob Rock mode on:
"prljavi bogatun!"
Bob Rock mode off.......
ZM mod on :
"My man!!"
;) |
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| widman |
| quote: | Originally posted by auplater
If you're not "affeared of it", you can dissolve a tap out of aluminum, using 40% nitric acid... quicker if you gently warm it up
won't touch the aluminum, but will dissolve the tap (might take soaking for awhile, preferably outside)... sometimes, the edges dissolve enough that the tap loosens and falls out.
I've done this many-a-time.
I also have a Sears broken tap remover, which has reverse threads... but requires a small hole drilled into the jammed tool, which ain't easy as described b4... better for softer jammed screws...
John L. |
I've used this method with good results. I've also used HCl to remove a tap from copper. The downside is disposal of the hazardous waste.
Pete |
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| richie00boy |
That's interesting, but isn't the speed of the drill a factor? I usually drill M3, and imagine I'd shred the hole with a hand drill. |
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| Peter Daniel |
Speed is not really a factor, most cordless drills offer two speeds anyway, and I always prefer faster rotation. The clutch setting is critical though. With proper clutch setting it's basically impossible to break a tap. It is also much faster and accurate, as controlling alignement is easier with power tool than doing it by hand. Once you try it, there is no going back ;)
I used a method described by Vikash as well (with placing the tap in a chuck of a drill press), but only few times, where perfect angle was really critical and tap size large. Otherwise, I don't bother. |
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| SheldonD |
one thing np pne suggested
Alominum has a larger coefficient of thermal expansion.
Heatind say an oven at 400 deg F may loosen it enough to use a scriber or small tool to umwind it. A bit of penetrating oil would help here as wll |
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| cowanrg |
ive broken taps before, its easy to get them out without a lot of complex methods if you understand the tap. its too hard to drill, its too brittle to grab and turn out, and its too diifficult to score it and screw it out. its weakness is its brittle.
get a nail set (or center punch, whatever). you might have to sand the top of the tap flat, so you can get a nice flat surface. put the punch on a flat part and bash away at it with a hammer. it should start to shatter. you can then dig out the pieces and it should come out. |
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| neutron7 |
If the hole is not blind and there are a small enough amount of threads
you can try this.
make sure to use eye protection! |
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