Help with removing rusted screws

Icecream_Gladiator

I'm having some drainage work done, which means I have to take apart a section of our timber decking. It's an older decking, maybe 10 years or so, but the timber, including the framing, is still in reasonably good shape.

The problem is that some of the countersunk screws are quite rusty and in a few cases the top/head of the screw just completely disintegrated leaving the rest of the screw and the threads embedded in the decking boards and the frame underneath holding it tightly together and impossibe to remove.

How can I remove a screw like this, preferably without damaging the timber or having to cut up the board.

After the work is done, I'd like to put the decking back in.

Bigphil1474

You could try drilling it out with a suitable drill bit - it may well disintegrate although the rest of the screw might be solid. Alternative would be to use a chisel or knife to clear around the screw a little bit to give you enough room to get some pliers or similar in to twist them out. Obviously you'd need to do some fettling when you put those bits back in. Might be other ways, but that's the approach I'd take. 

Eldi_Dos

Drill out, starting with small pilot (2mm) then use bigger bit to drill out enough of screw to lift decking plank off.

An alternative is use a thin hole cutter to take plug of wood around screw, then cut head of screw off with hacksaw.

fisher66

A multitool with a bimetal blade in it would allow you to cut off the shank of rusted in screws so the remains are flush with the wood after you've managed to get the decking off. You'd then have to put your new screws in a place in the decking when you refit.  If the old screws heads have not disintegrated then drilling them off or prizing the decking over them is all I can think of.

Icecream_Gladiator

What sort of drill bit would you recommend to drill out the screw?

I only have a 10v cordless drill, would that be enough power?

Bookworm105

Icecream_Gladiator said:

What sort of drill bit would you recommend to drill out the screw?

I only have a 10v cordless drill, would that be enough power?

try it and see. If the drill bit is sharp enough the main difference from a more powerful drill would be speed 

the important part is to start the drill bit in the dead centre of the screw, as what you are aiming to do is only remove the head of the screw, not drill down the entire shank of the screw or wander off into the wood. Ideally use a centre punch to mark the centre of the screw to give the drill bit a place to self centre itself when starting 

once the screw head has been removed, you can then lever the decking board up the shank of the screw ideally ending up with the board off and the screw shank still in the wood. You can then grip the shank in mole grips (or similar locking pliers) and manually unscrew the screw. 
Thus enabling you to put a new screw back in the same place - ideally the next size up in thickness of screw.

if on the other hand the original screw is threaded for its entire length and thus the wood cannot be levered off, you will need to drill the entire screw down to the depth of the decking board. if you are careful finish just above it, then lever off, and hope you have enough protruding from the joist to enable you to mole grip it and get the rest out. 

as for drill bit, obviously you use a bit intended for metal, not wood.
the cheap ones are called "jobber" drills as they do not last much beyond one job
if you have never drilled before then start with a bit that is the full width of the screw head. however as soon as you have established a pit in the screw head switch to much smaller drills and then go to the relevant depth and then, if necessary, work back up to the full sized bit in increments. A cheap set of metal drills from say 1.5 mm to 6 or 8 mm would only cost a few £ to buy

if you have an unsteady hand then get yourself a set of self centering drills (typically called hinge drills) and use them to get the starting pit established. They are however more expensive and you would still need to get a metal drill set anyway to get the full depth done 

here is a random google search result 
Hinge Drill Bit Set 3 Pieces - Screwfix

JohnB47

I know you're talking about screws but when I want to get rusted nails out I always give them a sharp tap (or three) with a hammer, to actually push them a bit into the wood first. This breaks the grip that rust creates.

I would suggest trying placing a suitably shaped piece of metal on the screw head (a big nail or old drill bit) and hit that firmly a few times with a hammer to hopefully break the rust grip. It might work and costs nothing to try.

Good luck drilling out a screw! I'll be impressed if you can do it.

Mr.Generous

I agree with JohnB47, you'll never drill out a woodscrew. I'd use a pry bar and wrench the wood out - you might need some new boards. If the head is very rusty you might be able to chisel a straight line into the metal with an old chisel and unscrew it with a flat head screwdriver - or the chisel.

You'd have a better chance running the cordless in reverse with a metal bit in pushing it hard against the screw, sometimes it actually backs a stuck screw out because its trying to turn it in the unfasten direction.

ROY47

https://www.toolstation.com/screw-bolt-extractor-set/p51010?store=FW&utm_source=googleshopping&utm_medium=feed&utm_campaign=googleshoppingfeed&mkwid=_dc&pcrid=null&pkw=null&pmt=null&gad_source=1&gclid=EAIaIQobChMIh6LupaPFhgMVJZZQBh272hFmEAQYBCABEgJA7PD_BwE&gclsrc=aw.ds

For a few pounds give them a try ? 

FreeBear

ROY47 said:

https://www.toolstation.com/screw-bolt-extractor-set/p51010?store=FW&utm_source=googleshopping&utm_medium=feed&utm_campaign=googleshoppingfeed&mkwid=_dc&pcrid=null&pkw=null&pmt=null&gad_source=1&gclid=EAIaIQobChMIh6LupaPFhgMVJZZQBh272hFmEAQYBCABEgJA7PD_BwE&gclsrc=aw.ds

For a few pounds give them a try ?

I have seen those things used in an attempt to extract seized bolts/studs. They invariably break, and the only way to get the remains out is with a spark erosion machine - If you can find someone with such a device, it is expensive.

Forget using those extractors on a wood screw - The shank is likely to be around 5mm diameter, and no where enough meat to drill a suitable hole. Best thing to do is to drill the head off and use a pry bar to get the plank up.

Don't waste your money on that extractor set, and if you do have a set in your tool box, throw the darned things out.

Bookworm105

FreeBear said:

ROY47 said:

https://www.toolstation.com/screw-bolt-extractor-set/p51010?store=FW&utm_source=googleshopping&utm_medium=feed&utm_campaign=googleshoppingfeed&mkwid=_dc&pcrid=null&pkw=null&pmt=null&gad_source=1&gclid=EAIaIQobChMIh6LupaPFhgMVJZZQBh272hFmEAQYBCABEgJA7PD_BwE&gclsrc=aw.ds

For a few pounds give them a try ?

Don't waste your money on that extractor set, and if you do have a set in your tool box, throw the darned things out.

100% agree.
My set sheared the first time i tried it, didn't replace it, went back to drilling out