Remove a stripped security screw?

[Jockose]

Installed a bracket to lock bikes against the wall but now need to remove it.
But can't seem to remember how I did it

grateful for tips

 

[harry73]

Is it not possible to loosen the screws?

 

[Alfredo]

But cannot seem to remember how to do it

Isn't it just a matter of unscrewing it with the right type of bits?

 

[Stefan N]

They're studying.

 

[Alfredo]

They are plugged.

So the hole to insert a bit is not there because there is a plug?

Yes, the idea is probably that they should be hard to remove. Maybe cut a screwdriver slot with an angle grinder or possibly a Dremel? I assume the plug is hard to drill, otherwise, you could just drill them out.

 

[Bassrunner]

Maybe there is some form of special key that fits the outside of the screw... I would probably try with the adjustable pliers, and if that didn't work, try drilling up, grinding down, or sawing off the head.

 

[harry73]

Can't you drill up a screw head?

 

[Stefan1972]

The middle one is probably difficult to drill...........The easiest way is probably to cut a notch in them with an angle grinder and then detach them. Then you could possibly also loosen with a sturdy flathead screwdriver.

 

[Kane]

If it doesn't work with a groove and screwdriver, make multiple grooves at different angles and knock off the head with a chisel.

 

[Jockose]

After X number of attempts and swear words, the solution came.
We took 2 nails and simply pried out the plugs.

This was about 10 seconds before the angle grinder came out.