How long will a security screwdriver insert last?

This article should really come with a health warning. Looking at how long a security screw drill bit or driver insert will last is almost as difficult to answer as the rhetorical ‘how long is a piece of string?' question. So much depends on the material a screw is being affixed to, how far the screw is tightened, who is carrying out the job and what setting they use on their drill! However, this article will in some way attempt to give some sort of guidance.

We recently tested drill bits on 100 x Snake Eye screws (pig nose screws), 100 x 6 Lobe pin screws (Pin torx screws) and 100 x Pin Hex screws. All the screws used were countersunk self tappers, all were 10 x 1" and all were attached to the same piece of wood using the same drill on the same, relatively high drive setting; this led to some interesting results.

Before this article reveals the results it is worth stating that our test is in no way scientific. Researchers would undoubtedly say one man using one drill type is in no way representative. In truth, for this to be anywhere near to being a meaningful test we felt at least 20 different people should be used. They should also be trying out different screws sizes and different material types. However, regrettably, we simply do not have the luxury of time or resources to carry out such a robust survey.

That said, the results of our test were still fairly illuminating. Over a sample of 100 screws the following is the number of drill bits used:

• Pin Torx security screws: 1 driver insert
• Pin hex screws:  2 driver inserts - 1 no longer useable
• Snake Eye screws: 4 driver inserts - 3 no longer fit for purpose

In honesty we were not entirely surprised by the results. After all, the Pin torx screw (or 6 Lobe pin screw as we refer to it on this website) has a higher torque value, whereas the snake eye screw has a relatively low torque. As such you would expect the drill bit to last longer.

So what has this article proven? Apart from you can tighten a 6 lobe pin screw more than a snake eye screw using a drill bit, its proven what many regular users of security screws already know. However, if it has done anything it may help those less familiar with security screws to think twice about the number of driver inserts they need when ordering their screws. After all, the last thing anyone ordering screws wants is to leave a job half way through to order another drill bit!