Loosen big old slotted screws in Wood

[john curzon]

Big very old slotted head screws in door jamb don't want to loosen. Any crafty tricks to encourage them please? I really dont want to damage the slots if possble.

[Andrew]

Drill small diameter hole down at angle to meet the middle of the embedded screw at right angles and drip some sort of release fluid down. Leave to soak in well, then try using an impact driver at a low setting ?.

I assume this is a ferrous screw that has rusted and swollen.

[john curzon]

Its a brass screw but its big and extra tight. When you say release fluid what did you have in mind....just oil ? Might that swell the wood fibres and just tighten things up ?

[alan_m]

Hammer/screwdriver. Give the screw a couple of whacks inwards before trying to turn it.

[Colin Bignell]

Also, tighten them slightly to begin with, just until they move. That way, you if you damage the slots in getting them to move, you haven't damaged the parts of the slot you need to be sound to unscrew them.

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[Clive Arthur]

That.

[Andrew]

It's a brass screw. A tad more brittle than a steel one.

[alan_m]

Make sure that you use a screwdriver that fully fits the diameter width of the slot and one that doesn't have too much play when fitted in the slot.

You may find that using a screwdriver with a long shaft works better. One where the shaft is a foot+ long.

If you can put a spanner on the screwdriver shaft you can press the screwdriver hard in to the screw but turn it with the spanner. Some screwdriver shafts have a square or hex section, often near the handle.

If paint in the slot is the issue have a sacrificial screwdriver. Heat up the end of the screwdriver with a blow torch or perhaps a gas hob and while still hot press in to the paint in the slot and turn. Don't expect the end of the screwdriver to be hard or properly tempered afterwards.

[Andrew]

What sort of wood is it ?. Is this an external frame ?.

If the latter then maybe remove as much paint as possible from the area around the hinge and get it nice and hot with a hot air gun. This might shrink the wood enough to allow you to jolt it loose by giving the end of the screwdriver a sharp whack while twisting anti-clockwise at the same time.

[Tim Lamb]

Nobody got a manual impact driver set then? Mine must be close to a fiftieth birthday:-)

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[Colin Bignell]

A screwdriver that fits the slot and a club hammer has always stood me in good stead. They usually only need an initial thump.

[Nick Odell]

Lots of good advice already - especially, IMO, making sure the screwdriver is the right fit for the slot.

I was taught to heat the screw up with a soldering iron tip and let it cool down again. This expansion and contraction, I was told, breaks the seal between the screw and the wood and the heat dries out the wood locally causing it to shrink away from the screw.

Works for me.

Nick [e-mail]

[Peter Able]

Along with all the other good ideas, make sure that the slot is ultra-clean. You might even slightly over-cut the bottom of the slot. That'll reduce the chance of damage.

PA

[alan_m]

Mine is around 50 years old - from when I had to work on the car every weekend to keep it going :)

I now have a cordless impact driver but I do find them not to good with slotted screws.

[nothanks]

Some ideas (all of which I've done many times):

- Heat it up using a blowlamp (if possible) or a big soldering iron

- After cleaning the slot, find a screwdriver that's a good fit (or grind one to fit) and give it a few healthy wacks in the slot before trying to turn it

- if it's steel: try an impact driver (manual sort in preference for this job)

- carefully drill down the centre of the screw with a small drill, then a larger one to take the screw head off. Core or dig out any screw remains, drill hole to sensible size and shape, glue a hardwood plug in the hole. Fit new screw.

[Colin Bignell]

It should be more ductile, unless it has dexincified.

[SteveW]

Or a mechanical impact driver (such as

- similar effect, but stronger jolts.

[Bob Eager]

I have. 55-ish in my case!

[Tricky Dicky]

The mechanical impact driver is best for slotted screws as you are striking it with a hammer it tends keep the driver head in the slot. If the slot is already damaged then nothing is going to move the screw and the only option is drilling out.

Richard

[alan_m]

On things such as hinges I've found that you only need to drill down to take the head off and once the hinge has been removed you are left with a bit of the screw shank. This can often be gripped and turned with a pair of (small) vice grips.

+1 for glueing in wooden plugs. In my 1908 house many of the doors have had multiple hinge replacement bodges over the years. In a couple of cases I've had to cut out the wood where the hinges fit and fit new blocks of wood but in others I've just drilled out in order to fit standard size wooden dowels.