removing security screws

amandaeb · Joined: 16 Feb 2004 Posts: 87 Location: United Kingdom

Does anyone know how I can unscrew security screws please? (the ones where the screw head is designed so that the screwdriver will only turn the screw clockwise)

I put up a cast iron door bell with them thinking it was a good idea at the time, now I want to remove it!

It's screwed into the porch door frame, which isn't very wide, 2" max, so I have to be careful how much damage I may cause.

Thank you in advance

Amanda

Kimba · Joined: 28 Feb 2004 Posts: 54 Location: United Kingdom

HSS drill bit I am afraid.

managed to once use a small swiss file to cut a sloted grove straight accross to top of the screwhead, and use a flat head screwdrive to remove it, but it's a time taking procedure!

AdamW · Posted: Thu Mar 04, 2004 12:45 pm

Alternatively you can use this

What you do is, drill a hold in the centre of the screw, screw in one of these (the thread is reverse to a normal screw, so you screw in anticlockwise). When it stops going in, the screw comes out.

Should cause no more damage than removing any other screw.

Good luck!

amandaeb · Joined: 16 Feb 2004 Posts: 87 Location: United Kingdom

Thank you Kimba and Adam,

Kimba, this may seem obvious, but.. what happens if I drill into the screw, does it cause the screw to turn and loosen? Do I have to use reverse? Hammer action? The security screws are 8's or 10's, should i just use a thin drill bit?

Adam, I saw a set of screw extractors in the local £1 shop. Look similar to the ones at Screwfix. If I need to use these, should the diameter of the hole I drill in the screw exactly match the diameter of the screw extractor, or should it be smaller? I'm wondering because on the one hand presumably it has to be able to bite, but, on the other hand will it be very hard to drive the screw extractor in if the hole is smaller?

Thank you again

Amanda

amandaeb · Joined: 16 Feb 2004 Posts: 87 Location: United Kingdom

I just wondered, one of the screws is not tightened up too close to the fitting, would a claw hammer extract this screw, or would it cause a lot of damage do you think? And require a lot of brute force?

Thank you

Amanda

AdamW · Posted: Sat Mar 06, 2004 9:14 pm

You will be able to pull out a screw with a claw hammer if you can get the claws under the head. It will chew up the wood a LOT when you pull it out mind! If you then want to screw something else into the old holes you could fill the holes, then drill new holes when it is dry and hard. If the filler will be hidden then that isn't a problem.

If the screw extractor is only £1, you may as well give it a go! If you look at the screw extractors on screwfix, they are a conical shape so you drill a hole and they will only go in so far. So I would think, drill a hole and see what happens. If you can't get the extractor in far enough to bite, drill the hole out a bit bigger and try again.

Good luck!

MANDATE · Posted: Sat Mar 06, 2004 10:37 pm

I have never seen a screw extractor small enough in diameter that is suitable for 8s or 10s woodscrew.
I would opt for drilling or grinding away the heads and after removing the bell, you will have the screws protruding slightly and should be able to turn them with mole grips.
Cutting or deepening the slot for a screwdriver is ok, but you will not achieve this with a swiss file. I use a rotary tool (B &Q £20) with a spindle holding a diamond disc ( diam 20mm width .75mm)

glocko · Joined: 24 Oct 2002 Posts: 77 Location: United Kingdom

What sort of area do you live in to have to security protect your doorbell???

AdamW · Posted: Sun Mar 07, 2004 11:18 pm

This little tool set specifies that it can extract from No. 6 to No. 12.

I am interested with the rotary tool idea: I have only ever seen a Dremmel used once, someone was trying to cut a hole in a metal ventilator grill. Nothing too substantial. And sparks came flying off!

Is this likely to happen if Amanda tries to cut a notch into the hardened steel screw heads?

MANDATE · Posted: Mon Mar 08, 2004 6:50 pm

Hi Adam.
The rotary tool is varible speed from about 1000 up to about 6000rpm.
The diamond discs do produce sparks but only in a mild form, nothing to get concerned about. B & Q only supplied non diamond grinding discs which soon wear down.
The tools you make reference to appear to be left handed which will have a tendancy to unscrew the screw when drilling, although I don't know how it bites into the screw in order to extract it.
Also I would not advise using a claw hammer as this puts pressure on the bell housing and if it is cast iron then it might break, cast iron is quite brittle althogh it is strong in compression

amandaeb · Joined: 16 Feb 2004 Posts: 87 Location: United Kingdom

Thank you to all of you who replied, sorry for the delay in responding..been working in the bathroom this week.

I've bought the set of screw extractors from the £1 shop and will have a go with them, not sure though if you use them to drill directly into the screw, or if you have to drill a pilot hole first. I suspect, on reflection, a pilot hole is probably a good idea as they may not be that hard being only £1!

Thank you for that tip about cutting a groove, but I don't have access to a suitable tool.

Glocko- I was probably being paranoid when I put it up with security screws-its not that bad here!

Thanks again

Amanda

masona · Posted: Wed Mar 10, 2004 9:46 am

amandaeb wrote:

I've bought the set of screw extractors from the £1 shop and will have a go with them, not sure though if you use them to drill directly into the screw, or if you have to drill a pilot hole first. I suspect, on reflection, a pilot hole is probably a good idea as they may not be that hard being only £1!

Yes,drill a small pilot hole first,might be easier to use a sharp nail punch to guide the drill bit.

I don't if I should be saying this as I kept quite on this one,you can use a very thin flat file type to make a straight line then modify a old screwdriver with a V or H-shape in the middle of the screwdriver flat bit then you can undo the screw with pressure at the same time.I properly get arrested now.

AdamW · Posted: Wed Mar 10, 2004 1:40 pm

MANDATE wrote:

although I don't know how it bites into the screw in order to extract it.

The screw extractors are tapered. This suggests that after you screw it in far enough then it won't go in any further. Then something has to give: either the screw splits open or it becomes unscrewed from the wood. Usually the latter happens (steel compared to wood) but I suppose it is possible to split the screw, especially if using too large an extractor.

Studders · Joined: 20 Feb 2004 Posts: 228 Location: Switzerland

amandaeb wrote:

Thank you to all of you who replied, sorry for the delay in responding..been working in the bathroom this week.

I've bought the set of screw extractors from the £1 shop and will have a go with them,

Thanks again

Amanda

Having tried these several times now my advice would be don't bother with them. They rarely work and often snap, leaving you in more of a mess.
I'd opt for grinding off the heads as suggested and maybe tapping the remainder below surface level and filling with a suitable wood filler.

MANDATE · Posted: Wed Mar 10, 2004 7:28 pm

Adam.
The bog standard 'screw extractor' I agree is tapered like a tap but with spiral grooves going anti clockwise.
To use these you have to drill a hole for the extractor to fit in.
The smallest in my set needs a hole about 3 to 4mm and this cannot be achieved on a 8s woodscrew.
The Trend snappy X appears to use a different method, looks like a countersink bit and it has to be turned/drilled in a anticlockwise direction.
I can only assume (without seeing it) that it bites into the screw head to undo the screw.
I think it would need a variable speed reversible drill.
Have you any experience with the Snappy X?