On 27 July, 10:28, tony sayer wrote:

I reckon there a lot better than Pozidrive, dunno why their not that
more used?..

Worldwide, Torx are more common than Pozidrive and have been since
some time in the '90s. Most "Pozi" screws (outside Europe) are
actually Phillips, which combine the worst of Pozi features with some
of those of the cross slot, particularly their weakness when formed in
a cheesemetal screwhead.

The great advantage of Torx is their good performance when the driver
is square-on, as for automated assembly. Their weakness is their
dependency on having the driver square-on, which makes them awkward
for maintenance later. This is something that Pozi and especially the
later improved Pozi, Superdrive?, are particularly good at.

Of course either are far better than something like a Bristol spline,
which only works when screw and driver are made from the best of
materials, in perfect condition. Some far-Eastern screws (Playstation
case?) are now using "Wankel" screws with a rounded triangular socket
in their head. It's a poor design, except for its compatibility with
weak cheesemetal screwheads, as it doesn't load the corners of the
socket..

Wikipedia has had a good article recently, "List of screw drives" or
somesuch. Best read it before some wiki****wit deletes it as "not
notable" or "original research".