PH vs PZ: The Screw Bit Difference Nobody Notices

Logosofia no Dia a Dia · Sep 17, 2026 · 26m

You've called every cross-head screw a Phillips. Half of them aren't. This episode untangles the real difference between Phillips (PH) and Pozidriv (PZ) — why the famous "designed to cam out" story is backwards, how parallel flutes and four little tick marks change everything, and what actually happens to a screw head when you grab the wrong bit. Along the way: a 1988 Wall Street Journal pan, a 1962 patent timing coincidence, a tradesman-versus-engineer argument nobody has settled, and the quiet reason assembly lines torque Phillips joints 15–25% below spec. Episode 5283 —…