Removing broken screws and other things

[brush-head]

hello I hope someone may be able to help or point me in the right direction. I have some tubular chromed chairs with leather back and seats. They've been up in the loft a few years and after cleaning them up am trying to reassemble them. The tubes are joined together with 2 inch self tapping (at least they look like they're self tappers)screws and a spacing sleeve.

Two of these chairs have one of the four holes that take these screws, blocked with a piece of broken screw. Now I know that I would drill these bits out but, not being a consummate DIYer, I thought I'd ask this group, the best way of doing this and if there are any gadgets around that would make this easier/safer. I obviously want to avoid damaging the thread that's been cut in the tubes by the previously unbroken screws.

The other question I have is how do I go about determining the size of the thread for these screws? Or do I just go trying various packets in B&Q and Homebase until I find the right ones - it's difficult on sites like Screwfix and can work out expensive if you get the wrong ones. Thanks for any help anyone can give.

[Harry Bloomfield]

brush-head has brought this to us :

If they are self tappers, you will find these are hardened steel, much harder than the material they self tap into - so impossible to drill and even if you could the drill would wonder into the softer steel of the chair frame. If you can't get them out with a self-grip wrench (or mole grips), then I would be inclined to try using an electric welder if you have access....

Deliberately get a welding rod to stick on the screw rather than form an arc, allow the rod to cool then use it to turn the screw out.

Find a local fixings supply company or a nut, bolt and screw specialist and show him a sample of what you require.

[Dave Plowman (News)]

You won't drill out self tappers - they're made of harder steel than a normal drill.

[doozer]

In my experience trying to drill out screws almost always ends up with the thread getting wrecked but maybe I'm just not cut out to drill screws out :-). I have had some success where I have clamped the piece and braced the drill with something.

You could try super glueing a small rod on to the end of the broken screw. I think you are likely to get glue in the thread though.

[Jeff]

If you cant grab 'em with pliers or wiggle 'em out with a small screwdriver then get a small punch and a big hammer :-) seriously just punch them into the tubing and then use a fatter self tapper.

Regards Jeff

[Rob Morley]

If there's room for them to fall through the other side of whatever they're screwed into then carefully attacking them with a drill might persuade them to do that. Otherwise self-tappers are very hard and won't really drill - the drill will probably slip and chew up the chair instead. If there's a bit of screw sticking out (or even if it's just flush) I'd try placing a small nut on it and then MIG- welding through the hole - hopefully you can then remove the screw with a spanner.

[andrewpreece]

If you can grind a slot on the remais of the shank you can use a screwdriver to unscrew the screw. A Dremel-type mini-tool is good for this, with a ceramic cut-off disc. Of course, if the screw is broken flush with the tube surface, some damage will be occassioned to the tube as well. You could reduce this by wearing the grinding disc down to a smaller diameter before using it to cut a slot in the screwshank.

Andy.