DIN 603 covers the dimensional requirements for carriage bolts. Reproduced below: the complete size table, the tolerance grades, and the companion and equivalent standards referenced when ordering to this document.
DIN 603 — Scope
DIN 603 specifies the dimensions and tolerances of carriage bolts. 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 603, alongside the related DIN 603 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 603
| Size | Pitch (mm) | Head diameter dk (mm) | Head height k (mm) | Square neck width (mm) | Square neck depth (mm) | Common length range (mm) | Reference standard |
|---|---|---|---|---|---|---|---|
| M5 | 0.8 | 13.0 | 3.0 | 5.0 | 2.5 | 16~80 | DIN 603 / ISO 8677 |
| M6 | 1.0 | 16.0 | 3.5 | 6.0 | 3.0 | 16~120 | DIN 603 / ISO 8677 |
| M8 | 1.25 | 20.0 | 4.5 | 8.0 | 4.0 | 20~160 | DIN 603 / ISO 8677 |
| M10 | 1.5 | 25.0 | 5.5 | 10.0 | 5.0 | 25~200 | DIN 603 / ISO 8677 |
| M12 | 1.75 | 30.0 | 7.0 | 12.0 | 6.0 | 30~240 | DIN 603 / ISO 8677 |
| M14 | 2.0 | 35.0 | 8.0 | 14.0 | 7.0 | 40~260 | DIN 603 / ISO 8677 |
| M16 | 2.0 | 40.0 | 9.0 | 16.0 | 8.0 | 40~300 | DIN 603 / ISO 8677 |
| M20 | 2.5 | 50.0 | 11.0 | 20.0 | 10.0 | 50~300 | DIN 603 / ISO 8677 |
Companion Standards
DIN 603 controls only the geometry of carriage bolts. 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 603
DIN 603 is still widely used in European mechanical engineering and as a cross-reference on legacy drawings; its ISO equivalent is preferred for new designs.