Torx screws are a modern screw bit with a six-sided star-shaped opening in the screw head. People will use a Torx screwdriver or screw in situations where they don’t want screws falling off the tip of the screwdriver, they don’t want to strip the head accidentally, or where they want to limit who can remove them. Torx is a trademark, so you also hear people refer to them generically as star drivers.
Torx screws as security screws
A regular Torx screw is not an ideal security bit, but if you want something more obscure than a regular Phillips or slotted head, it limits the possibility of just anyone being able to open the device.
But a proper Torx safety bit has a post in the center so a regular Torx driver won’t fit. To remove a Torx security screw, you need a special security bit.
Advantages of Torx screws
The major advantage of Torx screws is that the design of the head gives the bit a great deal of surface area, and the stress is spread out across more of the surface. While it’s possible to strip a Torx screw or drive bit, you are very unlikely to do it.
This makes them ideal in situations where stripping a screw is likely and also undesirable. Construction is one example. Another example is inside a machine that is objected to temperature extremes. Extreme temperatures, and especially extreme swings in temperature can cause a screw to seize. When a screw seizes, it is very easy to end up stripping the head, and then having to drill it out.
Where you may find Torx screws and need a Torx screwdriver
My first experience with Torx screws was in the early 1990s with an Amiga 500 computer. I always figured Commodore chose that type just to be difficult. Part of their motivation may have been to keep consumers from casually opening the machine purely out of curiosity, but undoubtedly it also cut down on the number of stripped screws in those cases.
I never liked how Compaq used Torx screws in their computers, but once I bought a proper Torx driver, I never dropped a screw in a Compaq case again. And to their credit, they used a dual slotted / Torx design, so if you didn’t have a Torx driver handy, you could still remove the screw with a conventional slotted driver. HP continued the practice after buying Compaq.
Others probably first encountered Torx screws when working on a car, a bike, or possibly even a lawn mower.
If you don’t have the right kind of driver on hand, Torx screws can definitely be a hassle. I’ve built up a reasonable collection of them over time, because a reasonably good hex bit set will usually include at least one or two of the more common sizes. And Torx headed construction screws usually come with a suitable Torx bit. And you can certainly buy an assortment of the most common sizes easily enough.
The size is designated by the letter T and a number from 1 to 100. The most common sizes are T10, T15, and T25. A Torx screwdriver will have the size printed or engraved on the handle. A driver bit will have the size engraved on one of the six sides.
How I became a believer
In 2014, I bought a house that needed a lot of rehab work. Among other things, it didn’t have any railings on its exterior steps. The friend who was helping me brought over a box of exterior construction screws with a Torx head. And I noticed he never had a screw slip off, and he never had any difficulty running a screw through any of the lumber.
They are more expensive, but they saved us a ton of time. I’ve bought Torx construction screws for all of my DIY projects ever since.