The use of specialty screws in defencive fences

The pin forces the drill to one side thus destroying the head of the screw. You can just grind it off but again you usually don't want to damage the surrounding enclosure and then you still have to remove the threaded section of the screw. This is only in the situation where you need to remove the screw to gain access then replace it with a more user friendly screw afterwards. If you just want to bypass the screw a grinder or a hammer and chisel are quick effective solutions. 🙂

actually that is the whole idea....drill to remove completely....no more screw but you are left with a larger hole

The trick is to remove the original screw so that it can be replaced with one of the same thread but a more user friendly head. If you drill it out you have to tap in a new thread. Sometimes this cannot be avoided but not having to drill out the original is always a good objective.

The trick is to remove the original screw so that it can be replaced with one of the same thread but a more user friendly head. If you drill it out you have to tap in a new thread. Sometimes this cannot be avoided but not having to drill out the original is always a good objective.

I agree, drilling out is the last resort

Robertson are great but for wood, or heavy/dense materials. Philips are just fine for light guage steel.

If you are looking into tamper proof fasteners, even in Canada I'd recommend going down to your local Brofasco or similar store. You can get a variety of fasteners with different heads (and the appropriate bit for your power drill). For instance, take a look at washroom partitions in a mall or airport. The fasteners have unique heads that can't be unscrewed without a specialized tool. There are a zillion types of heads out there, and chances are only if your in a particular line of construction is there a chance someone will have that particular bit to remove the screw... 🙂

Dang those are screws I thought they were rivets