Specification summary of DIN 571 as applied to lag screws (hex wood screws): the dimensions the standard controls, the tolerance and product grades it defines, the full specified size range, and the equivalent DIN/ISO/ASME designations.
DIN 571 — Scope
DIN 571 specifies the dimensions and tolerances of lag screws (hex wood 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
DIN 571, alongside the related DIN 571 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 DIN 571
| Nominal diameter (mm) | Pitch (mm) | Width across flats s (mm) | Head height k (mm) | Pilot/guide hole (mm) | Common length range (mm) | Reference standard | Notes |
|---|---|---|---|---|---|---|---|
| 5 | 2.0 | 8.0 | 3.5 | 3.0 | 25~100 | DIN 571 | Wood screw, self-tapping point |
| 6 | 2.5 | 10.0 | 4.0 | 4.0 | 30~150 | DIN 571 | Wood screw, self-tapping point |
| 8 | 3.0 | 13.0 | 5.5 | 5.0 | 40~200 | DIN 571 | Wood screw, self-tapping point |
| 10 | 3.5 | 16.0 | 6.5 | 7.0 | 50~250 | DIN 571 | Wood screw, self-tapping point |
| 12 | 4.0 | 18.0 | 7.5 | 8.5 | 60~300 | DIN 571 | Wood screw, self-tapping point |
| 14 | 4.0 | 21.0 | 9.0 | 10.0 | 60~300 | DIN 571 | Wood screw, self-tapping point |
| 16 | 4.5 | 24.0 | 10.0 | 11.5 | 80~300 | DIN 571 | Wood screw, self-tapping point |
| 18 | 5.0 | 27.0 | 11.5 | 13.0 | 80~300 | DIN 571 | Wood screw, self-tapping point |
| 20 | 5.0 | 30.0 | 12.5 | 14.5 | 100~300 | DIN 571 | Wood screw, self-tapping point |
| 22 | 5.5 | 32.0 | 14.0 | 16.0 | 100~300 | DIN 571 | Wood screw, self-tapping point |
| 24 | 6.0 | 36.0 | 15.0 | 17.5 | 100~300 | DIN 571 | Wood screw, self-tapping point |
Companion Standards
DIN 571 controls only the geometry of lag screws (hex wood 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 DIN 571
DIN 571 is still widely used in European mechanical engineering and as a cross-reference on legacy drawings; its ISO equivalent is preferred for new designs.