SECURITY SCREWS... A ONE-WAY PROPOSITION
Let NH help you to remove security and other screws with damaged heads
Security screws, also known as one-way screws, are very simple in design. They are available in either flat head or round head design in sizes ranging from #6 to #14. They are slotted screws, and can be installed with a standard slotted screwdriver.
Removing them is another matter. If you look at the graphic, you will see that half of each side of the slot has been smoothed down during manufacture. When you try to extract the screw, the slotted screwdriver tip rides out of the slot. Very ingenious design.
Security screws are used in applications where either theft or vandalism is common and expected, such as wall-mounted safes and public bathroom fixtures and enclosures... the latter being the largest and most common application.
Surprise!! There is an extraction tool, shown left. It looks much like a screwdriver, but instead of having a full-width slotted head, it has two hardened steel pins located in place of the slot. When used on a security screw, the two pins do not ride up on the curved surface of the security screw. Instead, they give just enough grip to turn the screw out. But...
Please don't run out and buy one... they're expensive and might not work!!
First, this tool is not easy to purchase. However, let me reassure you... there is no conspiracy to keep this tool from the public. Rather, it is used so infrequently that even the major hardware chains don't inventory it. Also, there are three sizes of this tool available... one for #6 and #8 screws, one for #10 and #12, and another for #14 and #16. At over $25.00 each, few people would want to own a matched set of these very specialized tools!
And as if the exorbitant price wasn't enough disincentive to buy, I was warned by the supplier that the tool was not guaranteed to work. For example, if the security screw was driven into a very solid wood stud or installed with a power driver, this tool will probably not work at all. So even those of us with "the right tool" are often left to find alternative extraction methods.
Security screws and stripped screw heads... birds of a feather
The easiest alternative is to grip the head of the screw with locking pliers (a.k.a. Vice Grips) and just turn it out. If you get a partial grip, but not enough to turn the screw, you can use a medium coarse file or rotary grinder (the Dremel is my favorite for small jobs) to slightly flatten two opposite edges of the screw head. This will improve the grip of the pliers. Do your filing carefully to prevent damage to the "whatever". You can protect the "whatever" with a piece of aluminum flashing... 6" step flashing is great for this. Cut a slot in it about 2" deep and the width of the screw head. Hold the flashing in place and work the file along the edge of the screw head while resting it on the flashing.
However, if the screw has a rotating sleeve on it... a type of hardened washer that will frustrate your efforts to grip the screw head... or if it is a recessed flat head screw, this method will not fly. What's a mother to do?
You can drill a hole into the head of the screw and use a screw extractor to remove it. Since you can't see the shank of the screw, a conservative estimate would be to drill a hole approximately 1/4 the width of the screw head.
A more severe extraction method would be to drill the head off the security screw. This is accomplished by starting with a small drill bit to drill a centered hole through the head. Then, use progressively larger drill bits till the head breaks off from the shank. Disassemble the "whatever" you're taking apart and use locking pliers to remove the threaded screw shank.
If none of the above methods work, you could always purchase a tactical thermo-'screw'-clear device at any fine munitions store near you.