The Posi-drive screw
 

On Wed, 16 Jan 2008 13:51:55 GMT, "George"
wrote:

what a naff invention...why couldn't they just put a square hole instead of
the cross hole?

Then again it was a yank idea

A few comments to save splattering replies everywhere.

Phillips screws were invented by the yanks and they are purposely
designed to cam out - they were widely used in mass production /
industry as a means of torque limiting. What is a purpose designed
feature has become in many eyes as a design flaw.

Posidriv was also invented by the yanks - the patent along with that
for Phillips screws is online and a simple search will find it, GKN
have the rights outside the USA.

Supadriv was a GKN only refinement in the late 70's/early 80's


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