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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What is a DIN number?

There are various sets of standards in the tool world.  In America we have The American National Standards Institute or ANSI for short.  On a global level, there is the International Organization for Standardization, or ISO.  Since this is a blog about specifically German made tools we will look at the German version: DIN.

DIN stands for Deutsches Institut Für Normung or German Institute for Standardization in English.  They have been operating for literally 100 years and have always been highly regarded in the standards community.  Though the name implies an exclusively German operation, the DIN standards have been adopted across the world and influenced many other standards organizations including the ISO.  The best example of this is the DIN standard 476 from 1922 introducing the A sizes of paper which would later become ISO 216 in 1975.Read More »