Screw extractor

Lots and LOTS of money. Trading off strength against toughness is easy - adding both is really expensive (and if it were cheap, the screws you are trying to extract would be made stronger *and* tougher - so you would be back where you started).

See "The New Science of Strong Materials" for an easy-to-read introduction to the problem.

Reply to
Martin Bonner
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I have found them ok in some cases. You need to drill a hole for them though. (you are more likely to have success on fairly substantial bolts etc rather than normal screws)

Quite often just drilling the hole with a left handed drill bit will do the job all by itself.

Reply to
John Rumm

Never used one of those, I'll have to get hold of some left handed drills.

Reply to
Mr Macaw

Don't forget to get a left handed screwdriver at the same time.

Reply to
Clive George

Are you April-fooling?

Reply to
Adam Funk

Don't think so. Eg:

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They are drills with the thread running the other way (so they will tend to exert a torque on the screw which undoes it).

Reply to
Martin Bonner

Reply to
harry

Yes.

Reply to
harry

In my experience also they very rarely work. Once you drill the screw head off, you can normally disassemble the parts, then you have a short length of shank exposed. Apply penetrating oil and let it soak. Grip the shank very firmly with a mole wrench. (Put a pair of flats on it if the diameter is reasonable). That will free up most things IME. For studs that are broken off flush, try to drill a small hole down the axis of the stud until it breaks through at the bottom. Successively increase the drill size until you just reach the tips of the threads in the hole. (You can't normally get the drill exactly central, so you reach the threads at one point). Once you have done that, apply a chisel to the remaining stud material near the break-through point. The stud should be sufficiently weakened that you can "collapse" the tube so that it becomes free in the threaded hole. In extreme cases, if you have managed to drill close to the axis, you can sometimes "unwind" the thread like a spring.

Reply to
newshound

Amusing to see that the photo clearly shows normal right handed drills.

Reply to
newshound

I've never had much luck with these.

Reply to
newshound

Never seen that design before. Only seem to be available from the USA, but they sell them singly, e.g.

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Not cheap but apparently a high quality alloy steel.

Reply to
newshound

Hmm, I guess the photo got reversed somehow!

Reply to
Adam Funk

Much as it might sound like it, no, I am actually being serious,

I have a set of drills that cut when spun in the anticlockwise direction. They are particularly good for drilling stuck fasteners, since the heat generated by the drilling combined with the direction of rotation will often spin out the stuck fastener. If they don't, then you still have a hole ready to try a stud extractor in.

(although if you snap off the hardened stud extractor, you are still in the same world of hurt!)

Reply to
John Rumm

Nah, he did what I often do on Ebay and take a picture form Google Images. He just wasn't that thorough in finding the right.... er left.... one.

Reply to
Mr Macaw

Some electric drills go slower in reverse.

Reply to
Mr Macaw

Those lefty folk are weird, I wouldn't be surprised if there was such a thing.

Reply to
Mr Macaw

Or if you snap off the special drill!

Reply to
Adam Funk

It isnt normally hard to get the broken bit of the drill out of what you were drilling when it broke.

Reply to
Thomas Johns

I was thinking mainly that the LH drills are rarer & (I assume) more expensive than normal ones. Of course if you have 3 stuck screws to get out, the drill is going to break on the first or second screw, & the neighbourhood pet food & DIY store won't stock those drills.

Reply to
Adam Funk

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