Hi John,
Norman Nock, British Car Specialists, Stockton, CA, wrote an excellent
description of Posidrive and Phillips heads. Now that I go to find it,
it's not findable.
In essence, though, what he said is that Phillips is a type that was
designed to release at a certain torque, so that fastenings could be
installed tight enough at which the bit would slip out.
Posidrive, on the other hand, doesn't slip. It's positive.
While the appearance is similar, Posidrive heads have four little
diagonal lines that radiate from the scredriver slot.
Mr Phillips and Mr Posi weren't the only ones to have ideas on this.
Reed & Prince made/still make some to their pattern, so there is ample
reason to blame the buggered screw head on the maker of the screw, the
maker of the screwdriver or the garage cats, rather than on oneself.
Bob
On Thu, 13 Nov 1997 15:36:09 -0800 (PST) "John J. Peloquin"
<peloquin@mamba.bio.uci.edu> writes:
>On Thu, 13 Nov 1997, Larry Macy wrote:
>
>=%O
>=%O
>=%O>I think these are actually pozi-drive rather than phillips!
>=%OWhat, is a pazi-drive screw?
>=%OPardon my ignorance.
>
>They look deceptively like phillips head screws and screw drivers but
>have
>sufficiently different geometry such that they will strip out with a
>phillips screw driver. IMHO, posidrive is a better design than are
>Phillips.
>
>=%O
>=%OLarry Macy
>=%O78 Midget
>=%O
>
>"Never ascribe to Malice that which can be explained by Ignorance"
>
>John J. Peloquin
>Molecular Biology &
> Biochemistry
>3205 BioSciences II
>UC IRVINE
>Irvine, CA 92697-3900
>jpeloqui@uci.edu
>
>
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