Specification summary of ISO 1173 as applied to cross-recess screwdriver bits (ph / pz): the dimensions the standard fixes, the full size range supplied, and the related designations commonly cross-referenced.
ISO 1173 — Scope
ISO 1173 specifies the dimensional requirements for cross-recess screwdriver bits (ph / pz).
Material, surface condition and any performance rating are set by separate documents specific to this part family — ISO 898-1 and ISO 898-2, which govern bolt and nut property classes, do not apply here.
Tolerance & Product Grades
Tolerances for cross-recess screwdriver bits (ph / pz) are given as limits on the individual dimensions in the table rather than as a fastener product grade.
Where a general-tolerance class is cited on the drawing instead, it applies to the dimensions not otherwise toleranced.
Dimensions Specified by ISO 1173
| Bit | Recess | Typical screw size | Distinguishing mark on the screw |
|---|---|---|---|
| PH0 | Phillips | M2 u2013 M2.5 | plain cross, tapered flanks |
| PH1 | Phillips | M3 u2013 M3.5 | plain cross, tapered flanks |
| PH2 | Phillips | M4 u2013 M5 | plain cross, tapered flanks |
| PH3 | Phillips | M6 u2013 M8 | plain cross, tapered flanks |
| PZ1 | Pozidriv | M3 u2013 M3.5 | cross plus four fine radial ticks |
| PZ2 | Pozidriv | M4 u2013 M5 | cross plus four fine radial ticks |
| PZ3 | Pozidriv | M6 u2013 M8 | cross plus four fine radial ticks |
Equivalent Standards
Where direct equivalents exist (ISO ↔ DIN, ISO ↔ ASME), they are listed on the parent Cross-Recess Screwdriver Bits (PH / PZ) page.
Always confirm against the dimensions on this page, since some "equivalent" standards differ in tolerances and head geometry.
Companion Standards
ISO 1173 controls only the geometry of cross-recess screwdriver bits (ph / pz). Surface finish is governed by separate finish standards (for example ISO 4042 for electroplating), and corrosion testing by ISO 9227 (neutral salt spray). Mechanical performance is set by the standards specific to this part family, not by ISO 898-1 or ISO 898-2, which apply to bolts, screws and nuts.
