Phillips or Pozi

[Dustydazzler]

Ok Today’s question...??

why do we bother with pozi head screws when we already had Phillips head screws....?

 

[James]

I wonder if they were developed for automatic feed Assembley machines etc?

 

[Ian1981]

Ok Today’s question...??

why do we bother with pozi head screws when we already had Phillips head screws....?

Because pozi are an improvement.
what I hate is screwdriver sets that come with Phillips instead of pz2, I never use my PH 2.

 

[nicebutdim]

List of screw drives - Wikipedia

en.wikipedia.org

Apparently it allows greater force to be applied. I don't know why either continues to be so widely used, considering the more reliable alternatives.

 

[James]

Because pozi are an improvement

Or because they had a patent and pozi worked around the patented idea?

 

[Mark Wright]

nearly all woodscrews I see nowadays seem to be Pozi.

 

[DPG]

Use a good PZ2 bit and good quality screws and it's amazing the grip they get.nuntil someone gets trigger happy and takes the edge off.

 

[nicebutdim]

Use a good PZ2 bit and good quality screws and it's amazing the grip they get.nuntil someone gets trigger happy and takes the edge off.

Problem I find is when someone drove the screw in with a cheap or worn driver. Unless you can get a decent amount of forcce on that head there's a good chance of camming out. This issue is greatly reduced with torx heads, although they're a pain with so many different sizes. I've never had a single issue with Robertson heads, although it may be their being relatively uncommon in the UK means that only quality screws and drivers are available...

 

[DPG]

Yeah that's the problem, people not matching screw head to driver. Same with brass screws when someone has used too small a screwdriver.

 

[Dustydazzler]

Yeah that's the problem, people not matching screw head to driver. Same with brass screws when someone has used too small a screwdriver.

I was always told with a flat head screw use a slightly over wide driver...

 

[DPG]

I was always told with a flat head screw use a slightly over wide driver...

As long as the screwdriver tip reaches the bottom of the slot in the screw.

 

[telectrix]

phillips, pozi, whatever. no screw can resist a hammer and chisel, or angle grinder.

 

[rsgaz]

Or because they had a patent and pozi worked around the patented idea?

Both were patented by the Phillips Screw Company!

US3108623A - Tools for recessed head fasteners - Google Patents

patents.google.com

 

[Lister1987]

If it's a matter of force applied to the screw, surely Robertson, Hex and Torx would be better choices?

 

[nicebutdim]

Both were patented by the Phillips Screw Company!

US3108623A - Tools for recessed head fasteners - Google Patents

patents.google.com

Both patents are 'currently assigned' to the Phillips Screw Company.


From the earlier posted wikipedia link:

"The Phillips screw drive (specified as an ANSI Type I Cross Recess) was created by John P. Thompson, who, after failing to interest manufacturers, sold his design to businessman Henry F. Phillips. Phillips is credited with forming a company (Phillips Screw Company), improving the design, and promoting the adoption of his product. The original patent expired in 1966, but the Phillips Screw Company continued to develop improved designs."

"The Pozidriv (sometimes incorrectly spelled "Pozidrive") is an improved version of the Phillips screw drive. It is designated "Type IA" by ANSI standards. The Pozidriv was patented by GKN Screws and Fasteners in 1962. It was designed to allow more torque to be applied and greater engagement than Phillips drives. As a result, the Pozidriv is less likely to cam out. It is similar to, and compatible with, the Supadriv screw drive"

 

[DPG]

And if that wasn't enough don't forget the Japanese JIS cross head.

 

[nicebutdim]

And if that wasn't enough don't forget the Japanese JIS cross head.

Turn up on electronic devices and really don't like PH or PZ drivers.

 

[DPG]

Identified by a small dot on the head I believe.

 

[nicebutdim]

Identified by a small dot on the head I believe.

That's supposed to be the case, but those that I've found have been tiny and unmarked.

 

[MJPD29]

List of screw drives - Wikipedia

en.wikipedia.org

Apparently it allows greater force to be applied. I don't know why either continues to be so widely used, considering the more reliable alternatives.

I can only imagine its because the mass of screws produced means they wre chepa to buy. I don't know any electrician here that uses them much, mainly square head used here.