I'm curious as to why use a hex and star drivers and fasteners instead of a square.

[Nealcrenshaw]

Not quite sure why more manufacturers and tool makers don't make square drivers and fasteners instead of using hex and star(torx) drivers and bolts which are much more likely to round off than a square driver and fastener would.A square driver would give tons of torque on the fastener.

Even if the the part to be fastened is round like a caliper bracket you could still use a round cap screw with a square recess,Which will make it alot easier if the bolt is rusted, which 8 times out of 10 they are. Any thoughts?

[eschoendorff]

It has to do with the assembly process. Torx is popular because it speeds up the manufacturing process and is more...uh... "robot-friendly."

[Merkava_4]

It's all about the surface contact area; the more, the better. Square slots sure beat Phillips though.

[Frank Elson]

the very last thing on a car makers mind is the poor sap who might have to take it apart again.
Rust ? Phooey, your problem mate, we have your money, and we made more by using torx fasteners so on yer bike.

[bchee]

It has to do with the assembly process. Torx is popular because it speeds up the manufacturing process and is more...uh... "robot-friendly."

I always wondered why square stuff wasn't used more myself. I think drain plugs use a recessed square or plug. Seems like square should be stronger.

According to wikipedia, Robertson fasteners were considered on Ford assembly lines, and were faster.
"When Henry Ford tried out the Robertson screws he found they saved considerable time in the production of cars but when Robertson refused to license the screws to Ford, he realized that the use of the screws would not be guaranteed and stopped using them.[1][2][3]"
http://en.wikipedia.org/wiki/Robertson_screwdriver

[Frank Elson]

There was a story in the 1960s that we all laughed at.
Ford stopped paintng the inside of their ashtrays. Saved something like 6 cents a car.
After the laughter had died down Ford reminded the world of motoring that they made Millions of cars world wide in a year...

[speed bump]

Most robertson stuff is nice until you have to get at it from an angle. Hex stuff you can get at it from an angle and since you have a round fastener anyway you can maximize contact area with a hex compared to a square.

As far as torx goes it was designed to be a better mousetrap than a philips which was a better mousetrap than a flat. It also has more contact area than a square drive as well.

[kwright]

I actually have a bit of experience in an automated manufacturing environment (not automobiles, though)... we were decided to transition from Phillips-drive due to "cam out" & stripping to something more auto-insert friendly.

Extensive testing was done, in concert with fastener and tool manufactures, both drivers and bits.

What we found (and were advised we'd find, BTW) was square drives actually had a nasty habit to friction weld to the fastener, that is, the tool would end up welding itself to the fastener in high speed, auto insert operations.

The star or torx drives simply didn't do this. Ultimately, we went with star drives, which eliminated the stripping and didn't bind to the fasteners.

[krusty the clown]

it seems that robertson drive screws are mainly used in the camper or conversion van industries........i thought it might have been an "indiana" thing!

[OctaneMotorsports]

Robertson = a very much Canadian thing. We fiend that shit.