Torx Screws, Torx Tools Available at KC Tool

A Brief Guide to Torx and Its (Many) Variations

­­We have discussed previously on this blog about the highly specific “Pentalobe” screw head and the tools used in conjunction. The Pentalobe shape is a relatively new invention compared to one its cousins, the Hexalobular screw, which many people call a star or Torx. Torx is actually a trademark of Camcar Textron, so the use of its name is another example of genericized trademark, like we use the term Allen Wrench for Hex Keys.

A Torx Screw Up Close and Personal, Made By Spax, KC Tool
A Torx Screw Up Close and Personal, Made By Spax

The original six pointed profile has similarities to a hex-end head but the sides are concave, providing six points opposed to sides. This creates essentially 12 points of contact opposed to the hex’s six, allowing for much more torque to be applied.  There is a theory out there that Phillips screws were INTENTIONALLY designed to cam out, so the screw would not be over-tightened in the end. Torx is just the opposite, as its design prevents the tool from camming out, providing a better grip in the fastener.

Torx screws are used in several applications, from automobiles to computers. They also come in a number of varieties. They come in external versions (for use in a socket wrench or ratchet), security (with a pin in the center of the screw head to prevent tampering), and what is known as Torx Plus. When the patent to the original Torx design was about to expire in the early nineties, Textron improved on the design by squaring off the lobes slightly to minimize wear and maximize torque. A standard Torx driver will fit into a Torx Plus screw, but a Torx Plus will not work in a standard so be sure to know which one you will be working with.

Finally, a note on sizing and nomenclature: One of the beauties of Torx sizes is that they are universal, meaning there is not an SAE vs Metric version. They are all the same. For the standard Torx, sizes are distinguished using a T before a number. The number is a point-to-point dimension that runs from T1 all the way up to T100. Some of the most common sizes are T10, T15, and T25, but there are many specialized sizes including T47 and even T5.5. If you need the security version, an S is added to the end of the number. External Torx use an E before their size, but do not correspond to the internal sizes. For example, an E8 external Torx is equivalent to a T40 internal Torx. And then rounding it all out is Torx Plus, which uses IP (internal plus) and EP (external plus) for designating size. Kinda complicated, huh? OH! Did I mention you can get them with a Ball-end as well?

Torx, Torx Plus, External Torx, Ball-End Torx, KC Tool
Left to Right: Torx, Torx Plus, External Torx, Ball-End Torx

There is one thing that is not complicated, though, and that is the best Torx tools can be found in one place, KC Tool.

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83 thoughts on “A Brief Guide to Torx and Its (Many) Variations

  1. Torx is the best, we only use torx screws. No slipping and the bits fit or they don’t, just perfect

  2. In order to adjust the valves on a Briggs and Stratton engine, a high quality T-20 hexalobular driver is required. I would like to have one that will stand up to the high amount of torque required to secure the lock nut on my valves.

  3. Awesome guide ! I work on Mercedes and always notice the different torxs, really good to know the importance of differences.

  4. Interesting to learn some torx history. I just purchased a T6 to install a ruggedized frame on a windows tablet.

  5. I see these used more and more often. I never realized they made ball end torx, but I’m sure they would be very handy at times. I’ll have to put a set on the wishlist!

  6. Torx fasteners are nice, I like how they don’t cam out like Phillips do. I have wera hex keys, and want to add a few sets of wera drivers to my tool box at home.

  7. The bottom line is that you get more surface area to grip on torx. I would love to add to my Wera collection with these.

  8. Haven’t a good set of torx drivers come in handy. Whether it’s for engine work or even installing a new sun visor., cheap ones break too easily or twist.

  9. This was a very interesting read. I don’t use Torx very often but I probably should after reading about the lack of cam out since that’s something I seem to be dealing with all the time when using Phillips screws. This is the first I’m hearing about ball end Torx, I have ball end hex keys so it makes sense, but it’s not something I would have thought to look up.

  10. Interesting info on the Torx design. I am getting to the point where I want to dispose of all the extra fasteners I have and just buy square, hex, and Torx from now on.

  11. Wera screw drivers are amazing. And pair them with the best fasteners drive?! Best drivers ever? Lol but on a serious not these screw drivers are really nice. Thank you KC tool

  12. Good to know about torx fasteners. After reading this it makes me want to expand in a set of dedicated drivers since I mainly use bits.

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