Torx and Torx-Plus

Found a bit for this brake-pedal attachment thing that the MotorCompany Service Manual calls a screw (torqued to 12 – 16 ft. lbs.), and the only thing that fits is a T40 Torx bit. I know this because I picked up an inexpensive bit at Home Depot to test the size since the fitment jumps straight from T30 to T40 with nothing in between. Reportedly the Derby covers require a T27 TorxPlus bit that has more square and flat “shoulders” and is therefore less prone to rounding over and causing a mellifluous cascade of swear-words to erupt. So with that thought in mind I got a T40P from the fine toolmaker S*K tools, that came via The Brown Truck of Happiness, as seen on the right.However the expensive T40P also has thicker splines and doesn’t fit the screw, while the cheap-o Husky one from Home Depot does fit, albeit not super snugly. And so as a belt-and-suspenders kinda guy, another T40P is winging (or flat-footing) its way here by USPS from eBay, made by SnapOn. Should come today, so we’ll see what the deal is.

UPDATE: What the deal is, is that I’m a dumbass. Spot the difference!So there’s a THIRD kind of Torx bit, the tamper-resistant variety…also with just FIVE lobes…oh well, I’ve got time to sort this out, and now I can tamper with things!

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12 thoughts on “Torx and Torx-Plus

  1. I work on instruments that use M2.5 screws to hold the covers on. T8 or T9 might work best, depending on the individual tool at hand. Also, JIS #0 screwdrivers which look like Phillips but are not. The JIS standard, I’m told, has expired, but the tools live on.

    • Thanks Ritchie, that’s precision stuff! I had to look-up JIS and what it was/is.
      The old joke told to me by a Harley Rider (AMF-era) about Harleys is;
      Harley Rider, “Can I borrow your biggest wrench?”
      BMW Rider, “Do you want 17mm or a 20mm or a 24mm?”
      Harley Rider, “Doesn’t matter, I’m going to use is for a f*ng hammer!”

  2. Torx Plus is only used on a very few HD bolts from a very few years. Mostly the ones that hold the rear fender on. Annoying when it happens but I don’t think they even had any on your year. I have both needed sizes in my toolbox as an HD mechanic and don’t think I’ve used either more than a couple times in ten years.

    I don’t like the tamper proof unless needed. They are thinner walled due to the holes and I have had them break when removing a frozen in bolt. There are no tamper proof Torx bolts on any HD ever made.

  3. Yeah, the five-lobe version is a REALLY rare bird. Only place I’ve ever seen it is on Apple products.
    In my opinion, the Torx design was revolutionary. It has about three times the grip of an Allen head, plus none of the tendency to cam out of a Phillips head. So you get more torque with a smaller head size, and no buggered-up screws needing special skills (and a large vocabulary of cuss words) to extract.
    Trouble is, when the Torx patent expired, everybody and their dog jumped in with their own “new, improved” version — every one of which requires their own specific bits.
    And that, in my further opinion, is a classic case of “re-inventing the wheel” and a gigantic PITA….
    Glad you got the brake-arm screw out.

    • It’s always when the patent runs out the “Industry Standard” goes to hell. Got the brake-arm screw out and swapped it the other part, and torqued back in with my little inch-pound torque wrench. The big old foot-pound Craftsman “Digitork” had given up the ghost, but the little one still had enough Newton-Meters left in it to do the job.

  4. Oh yeah, the saga of Torx bits… And my luck is, the ‘one’ I need is NOT the ‘one(s)’ I have… Sigh.

  5. Torx 101:
    To simplify matters, it’s only whether it is Torx or Torx-plus that matters. Any anti-tamper Torx bit has exactly the same *external* dimensions as the corresponding bit without the pin hole in the center. In other words, you can use an anti-tamper bit for any Torx fastener of the appropriate size and variety (Torx or Torx-plus).
    About 99% of all the Torx fasteners I’ve encountered have been the standard variety. Torx-plus seems to only show up in high-strength/high-torque applications. I would not buy a whole set if I were you; only the sizes you know you will need.
    Personally, when I’m toting my tool bag around all day (and therefore trying to keep its weight down), I only carry a set of anti-tamper Torx bits. In 14 years, I’ve only had to go back to the shop for something else once.
    There actually is a *fourth* variety: The wobble Torx bits that allow you to enter the head at up to a 15-degree angle from the centerline. Theoretically useful where there’s restricted access. But for whatever reason, that doesn’t seem to happen with Torx fasteners as often as it does with recessed-hex (Allen) fasteners. Speaking as a total tool junkie, I don’t own and have never needed a wobble Torx. (But I have needed and used wobble hex drivers a lot. Go figure.)
    A lot of Torx bit sets jump straight from T25 to T30. This is a big mistake, as T27 is a very common bit size for 5/16 and M8 screws. (Except in small stuff like electronics, the standard sizes are T10, 15, 20, 25, 27, 30 and 40.)
    To get a good fit and avoid stripping, clean any road dreck out of the splines of your fastener. Then, to take up slack and improve grip, smear a little valve-grinding compound on the splines of your bit. Works wonders….

    • I got the brake-arm screw out with the standard Home Depot T40. The big thing that caught me was the tamper-proof 5-spline vs. 6-spline, because on simply doesn’t fit in the other! The worst part is the refrigerator-cold garage floor.

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