Specification summary of ISO 1481 as applied to self-tapping screws: the dimensions the standard fixes, the full size range supplied, and the related designations commonly cross-referenced.
ISO 1481 — Scope
ISO 1481 specifies the dimensional requirements for self-tapping screws. 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 self-tapping screws 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 1481
| Size | Nominal diameter (mm) | Pilot hole (mm) | Pitch (mm) | Head diameter dk (mm) | Head height k (mm) | Plate thickness (mm) | Reference standard | Notes |
|---|---|---|---|---|---|---|---|---|
| ST2.2 | 2.2 | 1.7 | 0.71 | 4.2 | 1.4 | 0.5~1.0 | DIN 7976 / ISO 1481 | Cross-recess pan-head self-tapping |
| ST2.9 | 2.9 | 2.3 | 0.94 | 5.6 | 1.7 | 0.6~1.6 | DIN 7976 / ISO 1481 | Cross-recess pan-head self-tapping |
| ST3.5 | 3.5 | 2.8 | 1.27 | 6.9 | 2.1 | 0.8~2.0 | DIN 7976 / ISO 1481 | Cross-recess pan-head self-tapping |
| ST3.9 | 3.9 | 3.1 | 1.29 | 7.5 | 2.3 | 0.9~2.5 | DIN 7976 / ISO 1481 | Cross-recess pan-head self-tapping |
| ST4.2 | 4.2 | 3.4 | 1.41 | 8.2 | 2.5 | 1.0~2.5 | DIN 7976 / ISO 1481 | Cross-recess pan-head self-tapping |
| ST4.8 | 4.8 | 3.9 | 1.59 | 9.5 | 2.9 | 1.2~3.0 | DIN 7976 / ISO 1481 | Cross-recess pan-head self-tapping |
| ST5.5 | 5.5 | 4.5 | 1.81 | 10.9 | 3.3 | 1.5~3.5 | DIN 7976 / ISO 1481 | Cross-recess pan-head self-tapping |
| ST6.3 | 6.3 | 5.1 | 1.81 | 12.5 | 3.8 | 2.0~4.0 | DIN 7976 / ISO 1481 | Cross-recess pan-head self-tapping |
| ST8.0 | 8.0 | 6.7 | 2.12 | 16.0 | 4.8 | 2.5~5.0 | DIN 7976 / ISO 1481 | Cross-recess pan-head self-tapping |
| ST9.5 | 9.5 | 8.0 | 2.12 | 19.0 | 5.7 | 3.0~6.0 | DIN 7976 / ISO 1481 | Cross-recess pan-head self-tapping |
Equivalent Standards
Where direct equivalents exist (ISO ↔ DIN, ISO ↔ ASME), they are listed on the parent Self-Tapping Screws page. Always confirm against the dimensions on this page, since some "equivalent" standards differ in tolerances and head geometry.
Companion Standards
ISO 1481 controls only the geometry of self-tapping screws. 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.
