Phillips Drive (Type I Cross)
Direct Answer
The Phillips drive (Type I cross recess) is a self-centering cruciform drive system invented by John P. Thompson and commercialized by Henry F. Phillips in the 1930s (ANSI Type I / ISO 4757). Engineered with curved flutes and intentional cam-out torque limiting, it revolutionized high-speed automotive and aircraft assembly.
Source: ISO 4757 / ANSI/ASME B18.6.3 (Type I Cross Recess)
Specs
| Standard Specifications | ISO 4757 (Cross recesses) / ANSI Type I / DIN 7962 |
| Drive Geometry | Cruciform 4-wing cross with rounded corners and 57° tapered flanks |
| Self-Centering Capability | Yes (Driver tip automatically centers into recess) |
| Intentional Cam-Out | Yes (Designed to cam-out when tightened to prevent over-torquing and thread stripping) |
| Common Sizing Tiers | PH000, PH00, PH0, PH1, PH2 (most common), PH3, PH4 |
| Common Screw Pairings | Drywall screws, PC cases (#6-32), general wood and machine screws |
The Purposeful Cam-Out Mechanism
Before the invention of modern electronically torque-regulated power tools, assembly line workers frequently snapped screws or stripped tapped threads. Phillips engineered the cruciform drive with a 57-degree wall taper: when rotational resistance exceeds a set threshold, the screwdriver bit climbs out of the recess ('cams out'), protecting the screw shank from catastrophic torque shearing.
Modern Frustrations with Modern High Torque
In modern woodworking and construction using high-torque impact drivers, Phillips' intentional cam-out mechanism becomes a major liability, rounding off ('stripping') the screw head. This has led to the widespread adoption of Pozidriv, Torx, and Robertson drives.