Originally Posted by
Shimagnolo
This is interesting:
"Where Phillips heads were designed to cause the driver to cam out, to prevent over-tightening, TORX heads were designed to prevent it."
Ref:
http://en.wikipedia.org/wiki/Torx
Well, I must say the Phillips design has been a smashing success.
A friend of mine learned the hard way about using deck screws with Phillips heads versus Robertson (square) head screws. Though Robertson screws don't have the effeciency that Torx do, they are a lot better than Phillips heads. Your hands get a lot more tired trying to drive in Philips deck screws in and hope they don't cam out before the screw is completely in place as opposed to a Robertson head which will happily keep going until the screwdriver's chuck recognizes that it is at its max torque setting.
I do know one good use for the Phillips design -- tamper resistance. I screw one in, and if I interchange bits with a Pozidriv, it rounds out in a hurry making it impossible to extract without power tools.