Removing Security Screws

chasroberts

chasroberts

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I need to rebed/reseal a hatch but on examination I found that there are four security screws amongst the forty or so holding the hatch in. They are the type you can scew in but not out as the slots are slanted to avoid removal.

I appreciate that they will probably have to be drilled out but having tried this before on another similar type screw found the task impossible with drill bits refusing to bite and wandering off. So my question is; does anyone have a reasonably foolproof method of getting these little blighters out? I have a set of bolt screw removers but obviously need to get a pilot hole into the screw head before I can use them. Grrrr. Whoever put them in probably thought it was a good idea at the time!

All thoughts and ideas appreciated.

Many thanks in advance.

Chas
 
Things I have tried that may work:-

For drilling out I'd try using a dot punch in the centre to give a start point then use a small drill bit to establish a hole - about 2-3mm seems to work quite well - before working up in sizes. Either keep going until you've drilled out all the screw or use a stud extractor when you have a big enough hole.
Another method to get started would be to use a small grinding head on a Dremel instead of a dot punch.

Alternatively you could try a small grinding wheel on a Dremel to take the head off so you can remove the hatch, then grip the stump with mole grips to remove the shaft..
 
Presumably the heads are c'sk, precluding making a screwdriver slot with a narrow slitting disc in an angle grinder.
I'm not a great fan of L/H screw extractors. If one breaks off and jams in, you can be in a worse position than to start with.
If I were in this position, I think that I might look for a L/H jobber drill ( google) of suitable diameter to try to drill the screw out. Then the torque/jamming plus heating effect of the drill will tend to unscrew it.
Most DIY drills will run "backwards", hopefully the chuck won't screw off!
Just a suggestion, I've never tried it.
 
Use a dremmel with a small diamond drill bit ( procured from a friendly dentist). Cut a new slot and use a flat point screwdriver.
 
I would start by using Lodesman's method, but a short cut that often works is to tap the tang of a small flat file into the hole. Files are extremely hard and will cut through many lesser steels. If the bolts are not too tight you should be able to unscrew them with the file. Don't tap too hard or be tempted to turn with a big spanner - files are also quite brittle. If it doesn't work just keep going to bigger drills.
 
A further thought - now tried but only in the comfort of my garage, and on a large enough bolt - use a small drill to put two small holes into the head, equidistant and on opposite sides of the centre, and then use circlip pliers to turn it.
 
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sarabande said:
Screwfix (bless them) sell security bits to undo security screws.


http://www.screwfix.com/p/security-bit-set-33pcs/96872



I am told they fit the devices which fasten the the small radar speed detectors, I am told....


Or if you have an inclination to DIY, here's how to make your own.

http://www.johnath.com/projects/securitybits/



More info on security screw types.

http://resources.tannerbolt.com/articles/what-type-of-screw-is-this/
Click to expand...

Those are tamperproof screw heads. The OP's problem is that he has screw heads that are designed to be impossible to undo, for thief-proofing.
 
I bought a very impressive set of bicycle security skewers and fiendish nuts. And I have a Land Rover that I needed to defeat the steering/ignition lock on. In both cases, a small cold chisel did the job.
 
Using a small punch tap them round until they are undone sufficiently to get hold of with a pair of vice grips ( mole wrench)
 
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I have used the lh drill method, always drill lh when dealing with a mangled screw, get some for your toolbox, about 50% just come right out in a few seconds
 
Using a flat drift tap the screw many times to loosen the bond between the screw and substrate. Then apply WD40. Leave overnight. Then try any of the above suggestions.
If you are going to try and drill stainless screws, make sure that the drill bits are razor sharp, and use low speed avoiding any heat build up
 
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