ISO 1481 is the international standard for self-tapping screws. This page sets out what the standard governs, the size range it specifies, and the related standards you will see referenced in datasheets.
ISO 1481 — Scope
ISO 1481 specifies the dimensions and tolerances of self-tapping screws. Material, property class, surface finish and packaging are governed by separate documents in the same standards family (for example ISO 898-1 for the mechanical property classes of bolts and screws).
Tolerance & Product Grades
ISO 1481, alongside the related DIN 7976 / ISO 1481 entries on this site, specifies product grades (typically A or B for fine work and C for general engineering) and tolerance classes for the controlling dimensions. Choose the grade against the precision your application requires.
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 |
Companion Standards
ISO 1481 controls only the geometry of self-tapping screws. The mechanical strength is set by ISO 898-1 (bolts and screws) or ISO 898-2 (nuts); the surface finish is governed by separate finish standards (e.g. ISO 4042 for electroplating). For corrosion testing, the relevant document is ISO 9227 (neutral salt spray).
When to Specify ISO 1481
Choose ISO 1481 for international engineering work and OEM supply where ISO standards are the contractual reference. It is the default modern specification for self-tapping screws.