Hey, Thanx Evan. I know I have like 3 or 4 sizes @ home. Just needed be sure. I wonder why they came out w/those?

as far as I know they came out with them because it is difficult to use a torque wrench with a phillips head screw and get the proper torque, it is "supposed" to be easier to get the correct torque using a torx head. Personallyt I can't say I like them, the drivers tend to strip (and the screw heads too) but they are being used so we just have to live with them.

Actually, it has little to do with torque wrenches.

The torx fastener's primary reason for bieng is mass production. On the assembly line, it might be your job to install 240 threaded fasteners per hour. If you try to put a phillips screw on a power driver (electric or pneumatic), chances are pretty good, even with a magnetic bit, that it won't line up with the threads into which it is being inserted. A torx will. They stay on the bit better, therefore an assembly worker can install more fasteners correctly per hour.

And the advantage over Allen/Internal Hex is that it is easier to get onto the driving bit.

The consipracy theorists said, when the torx first came out, that the reason was that the manufacturers didn't want you working on your car. At that time, Torx drivers were not readily available. Not true today, so that blows that theory out of the water.

Yes, mass production is what I've always been told was the driving force behind Torx which was apparently invented by/for GM. I understand it gained its real popularity and general acceptance once it started getting used in robotic production lines. The extra gripping area of the star design gives makes for both better holding by the drive bit and more torquing ability out of the same size fastener head. I've run into small Torx a fair bit, mostly in automotive and electronic stuff, and the odd large Torx such as my old 140 hinges. I think it's a great fastener, but it's one more collection of drivers and bits you have to keep in the workshop. When you don't use them frequently they are always at the bottom of the toolbox.

I really have to believe the conspiracy theorists. I think the general acceptance of Torx was, in part, due to the failure of the "No User Servicable Parts Inside" warnings, which serve mostly as a challenge to the likes of me. As was mentioned, in the early days, the chance of your average clod having access to a full set of Torx bits was remote. Torx is also useful in minimizing tampering of items for warranty or liability purposes.

Need more proof of a conspiracy? Then how come so soon after Torx bits became available in your local hardware store they invented the Security Torx bit? These are the Torx heads with the center pin. I've got the bits, but I've only run into the screws once. The neat thing is you only need to own Security Torx bits as they work just fine in standard Torx heads.

And now that you mention it, I always wondered why the square head (more properly called Robertson) wasn't more popular in the U.S. They are obviously superior to both Phillips and slot head in many regards and don't require the more complicated and tighter production tolerances of Allen (hex) and Torx (star). Turns out it's due to Mr. Robertson (of Ontario) refusing to sellout his patent rights to Henry Ford way back in 1908. Some years later, Ford reached agreement with Mr. Phillips (of Oregon) to use his newly patented cross-style screw head on the production line instead of the old slot head. Ford apparently regretted that decision because of the tendency for workers to over-torque Phillips screws. With a Phillips head, a worker tends to really lean on the driver to keep it from skipping in the screw head, hence the tendency to damage the screw head or the assembly when the screw hits bottom.

Robertson heads come in just 4 sizes, #0, #1, #2, #3 using colour coded driver handles, yellow, green, red and black. Unfortunately, Phillips heads, apparently to get around patent issues, come in all sorts of sizes, tapers and nose depths. If you find yourself in a bind and only get to use a Phillips screwdriver, make it a vodka with milk of magnesia. :)

Unfortunately,

> Phillips heads, apparently to get around patent issues, come in all

> sorts of sizes, tapers and nose depths.

Ummm, no they don't. The term "Phillips" only refers to ONE type of crosspoint screw/driver. There are only a few more sizes than Robertson:

#00, #0, #1, #2, #3, and #4

Now, there ARE other types of cross-point fastener head. And this is where you get into different tapers and nose depths.

In the early 50's, the Posidriv screw head was manufactured by the Phillips Screw company. Here is an article about Posidriv screws. They allow for more torque to be used before the tool slips out of the fastener.

Yet *another* cross-point screwdriver is the Reed & Prince. Why? dunno.

Here is more info:

===

There are 3 different screws and screw drivers that all look somewhat the same but are not interchangeable.

1. Phillips (most common of cross point style screws)

A. Straight side ramps, rounded nose.

2. Reed & Prince (used mainly in aircraft and marine apps.)

A. Straight side ramps with sharp pointed nose, steep ramp angle.

3. Posi-Driv (used in GM vehicles since early 80s)

A. Curved side ramps, extra flute between ramps and curved nose.

===

So THERE! There is only ONE Phillips screw!

Thanks, Evan, you're quite right. I actually did know Phillips was only one of many types of cross-points. A bit like saying "xerox" instead of "photocopy". I didn't want to even get into all the hybrid fasteners I've seen in the catalogues -like heads that will take either slot, cross or square drivers. I've bumped into that one in AC electrical fixtures. Great for the ham fisted -if one driver happens to strip the head then maybe one of the others will still grab it.

And as long as we're picking nits, I must confess that the #0 (yellow) Robertson I mentioned is probably not included in Robertson's original patents. I didn't bother to check if it has since been formally recognized as a Robertson by industry. However, it is the only other square socket a consumer is likely to run into and consequently is sold alongside true Robertson drivers.

Gosh, this is getting a bit too fastenating.

There are square drive screwdrivers and screws used mostly in Canada called Robertson or Scrollux which will stay on the end of the screwdriver. I always found them easy to use. I just think the manufactures wanted us to buy more tools.

The robertson is great, but for some reason the american manufactures (and maybe others) don't want to use it. It is mainly used in Canada because it was invented here. Oh well. And I stand corrected about the tourque wrench idea, just something I had heard and it made it bit of sense (after all it is almost impossible to torque a phillips head screw properly). The ease of manufacturing make sense too I guess, though I still don't really like torx screws:)

The Robertson/square drive screws never took off because for years, it was a proprietary system. You want square drive screws? Gotta buy 'em from Robertson. Tools? Same deal.

Also note that while the US now sees square drive wood screws, it is damn near impossible to gind a square drive machine screw.

I personally use only square drive wood screws.

well then obviously that is the reason that the manufactures didn't want to use them (I did say that there was some reason I didn't know that they weren't using them). I wan't implying a conspiracy or anything. Thanks for supply the reason though.

"I personally use only square drive wood screws."

You musta found a bucket of 'em in the back of an old (free) Volvo. The tool, too.

There's where you're wrong, Don. I spend the dough when it's right. Fact is, I could get about a zillion free philips screws, but I choose to BUY square drive - I think they are THAT superior.

I'll say this, Evan:

When it comes to that stuff, you're sure a square shooter!

Don Foster (near Cape Cod, MA)

I don't draw real well, but a torx bit looks like a mutant Phillips.

no it doesn't. it looks like a mutant Allen/internal hex. Except the sides are convex, not flat.

I told you I can't draw.