Embedded SiBronze screw

Roach1948

Roach1948

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www.dallimoredesigns.nl
As I was in such a rush for the launch week before last I delegated some tasks to friends - the easy tasks ofcourse. One of them was to screw down the Ligneum Vitae sheet leads. This friend has a plastic yacht and is actively doing her up, so I thought a task like this would be no big deal for him.....

Erhh No!

Get back to find mashed screw heads on all the screws and a broken screw half an inch below deck level that has been rained on now for a week! Before you mention it I provided correct screw driver size and pre-drilled the pilot holes with correct size drill bit.

Anyway, my question is, how the hell do I get this half broken screw embedded from half an inch inside my mahogany deck...?
 
Find a small piece of metal pipe with an internal diameter just larger than the screw. Cut some 'teeth' into the end of the pipe, and put the other end in a drill. Then cut down and around the broken screw to a depth below the bottom of it. With a bit of jigery-pokery and several 'recuts' of the pipe teeth, you might be able to get it out.

The alternative method is slightly more ugly, involving a big hammer and a chisel.
 
Only thing I could think of is to drill off the heads and loft the sheet leads then re-do the job after drilling out, plugging and sealing the remains! A small core drill might cut round the remains of the screw enabling you to remove it prior to plugging. There are some machanics tricks for removing seased bots that you could possibly try - bolt extractor which is a left hand tap that would go into a hole drilled into the screw - designed for bolts and works quite well on them but and not tried them on screws and I dont think there would be enough 'meat' on the screw, would probably just shear the shaft - Freezing, use plumbers freezing compound to cool the screw but again its designed for metel on metal bolts and works by shrinking the bolt, doubt it would give enough play to get a screw out of wood
 
If you can drill a pilot hole down the centre of the broken screw, the extractor (Axminster Power Tools are cheapest I've found) will most likely work because the screw is new. The ones I'm trying to get out are decades old and crumbling. I have made a guide hole in a small length of steel rod which slots into the screw hole and helps to keep the drill bit centred. If you are buying the extractors buy a few because they are brittle, and do tend to snap.
Best of luck.
 
Yep. Agreed - a small "core drill" and run ir round the broken screw. once you clear the screw the center "core" usually breaks feww from the wood and teh core and broken screw can be extracted easily.

Undertook some serious furniture restoration a few years ago and a set of core drills was invaluable for removing broken screws on disassembly and for removing the odd screw that was broken on reassembly. Made a set covering #4 upto #14 screws. Simply plug the holes left after removing the core and fix new screws.
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"Artificial intelligence is no match for natural stupidity"
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[ QUOTE ]
Find a small piece of metal pipe with an internal diameter just larger than the screw. Cut some 'teeth' into the end of the pipe, and put the other end in a drill.

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They make these things and I think they are called "unscrewums" and are probably available for the US. Cheap now, even if you get bounced for the VAT.

The real answer - never let anyone else loose on your boat, not even with a sander!

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I'd be leary of using HS or carbon steel screw extractors. If one of those breaks off down the hole you'll be left with something that will corrode and rot your deck. Might be better to accept the broken bronze screw and a shallow plug.

Do let us know how you get on with this.
 
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