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I have a piece of moulding on an appliance that is held on by a long, thin screw with a hex head. The screw is perhaps 5" long and perhaps 1/8" diameter (modestly heavier than a wire coat hanger).

The overall dimension of the channel is slightly larger, but not substantially so. The channel has no gaps or openings that would allow me to pry the remaining screw through.

When attempting to remove the moulding to replace a light bulb I noticed a lot of resistance on the screw. I applied penetrating oil, waited, jiggled, repeated a few times and finally managed to snap the head of the screw off along with perhaps 1/2" of the shaft. The shaft is now recessed within the moulding by 1/2"

I now realize that the screw is seized at the bottom as well. I cannot access it from the bottom, or else I could just drill out the bit of threading at the bottom and be done.

What sort of bit could I use in a cordless 18V drill to remove this safely?

Is there another technique that would be applicable given that I cannot replace the moulding and thus must make a serious attempt not to damage it?

At present I envision using a longer drill bit to completely eat away the existing screw and then replacing it.

  • A couple of pictures of the situation might be helpful – James Van Huis Jan 23 '12 at 16:43
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+25

Have you tried using a Screw Extractor bit?

They are made for this purpose. You basically put it into your drill and when the drill slowly turns in reverse, the bit bites into the screw and tries to unscrew it simultaneously.

  • I haven't seen these before, I will investigate if they come small enough to be of help. – Stephen Jan 25 '12 at 19:32
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Chuck the protruding end of the screw into your drill (as you would a drill bit). Put the drill in reverse and try to back it out that way.

  • 1
    Good technique. but it could break it even further.. since already only using hand power broke it.. but the chuck will give good grip .. Good tip – Piotr Kula Jan 20 '12 at 17:14
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    Added edit to indicate that the shaft is now recessed within the channel and is not gripable (or Mr. Vice Grip and I would have solved this :) – Stephen Jan 20 '12 at 17:35
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You might be best served by filling the channel with epoxy, so it grips the remaing screw stub, letting that harden, drilling a pilot hole in the epoxy, and threading for a new 1/2" long screw. If the long screw was originally in there for vibration prevention, the above kludge should work as well since you're still attached to the original screw stub. This is hardly an optimal solution, but you've got to go with something that is reasonably possible. Done properly, you will still be able to disassemble the end result if you need to get in there again.

1

I've had good luck removed stripped screws with this screw extractor set:

Grab-it set

You use the cutting end to cut a new hole into the top of the screw, then you flip it around, push hard, and use the other end to grip the hole that you just made.

  • As with @Mike's answer, I'll see if these come small enough, they might be a solution. – Stephen Jan 25 '12 at 22:05

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