DIN 939 is the international standard for studs & threaded rods. This page sets out what the standard governs, the size range it specifies, and the related standards you will see referenced in datasheets.
DIN 939 — Scope
DIN 939 specifies the dimensions and tolerances of studs & threaded rods. 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 939, alongside the related DIN 939 / DIN 975 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 939
| Thread size | Pitch (mm) | Point type | Common lengths (mm) | Reference standard | Notes |
|---|---|---|---|---|---|
| M4 | 0.7 | M4 | 10~100 | DIN 939 | Stud, equal thread both ends |
| M5 | 0.8 | M5 | 10~120 | DIN 939 | Stud, equal thread both ends |
| M6 | 1.0 | M6 | 12~160 | DIN 939 | Stud, equal thread both ends |
| M8 | 1.25 | M8 | 16~200 | DIN 939 | Stud, equal thread both ends |
| M10 | 1.5 | M10 | 20~250 | DIN 939 | Stud, equal thread both ends |
| M12 | 1.75 | M12 | 25~300 | DIN 939 | Stud, equal thread both ends |
| M14 | 2.0 | M14 | 30~300 | DIN 939 | Stud, equal thread both ends |
| M16 | 2.0 | M16 | 35~300 | DIN 939 | Stud, equal thread both ends |
| M18 | 2.5 | M18 | 40~300 | DIN 939 | Stud, equal thread both ends |
| M20 | 2.5 | M20 | 45~300 | DIN 939 | Stud, equal thread both ends |
| M22 | 2.5 | M22 | 50~300 | DIN 939 | Stud, equal thread both ends |
| M24 | 3.0 | M24 | 50~300 | DIN 939 | Stud, equal thread both ends |
| M27 | 3.0 | M27 | 55~300 | DIN 939 | Stud, equal thread both ends |
| M30 | 3.5 | M30 | 60~300 | DIN 939 | Stud, equal thread both ends |
| M36 | 4.0 | M36 | 70~300 | DIN 939 | Stud, equal thread both ends |
| M42 | 4.5 | M42 | 80~300 | DIN 940 | Stud, equal thread both ends |
| M48 | 5.0 | M48 | 90~300 | DIN 940 | Stud, equal thread both ends |
| M4 | 0.7 | Fully threaded | 1000/2000/3000 | DIN 975 | Fully threaded rod, cut to length |
| M5 | 0.8 | Fully threaded | 1000/2000/3000 | DIN 975 | Fully threaded rod, cut to length |
| M6 | 1.0 | Fully threaded | 1000/2000/3000 | DIN 975 | Fully threaded rod, cut to length |
| M8 | 1.25 | Fully threaded | 1000/2000/3000 | DIN 975 | Fully threaded rod, cut to length |
| M10 | 1.5 | Fully threaded | 1000/2000/3000 | DIN 975 | Fully threaded rod, cut to length |
| M12 | 1.75 | Fully threaded | 1000/2000/3000 | DIN 975 | Fully threaded rod, cut to length |
| M16 | 2.0 | Fully threaded | 1000/2000/3000 | DIN 975 | Fully threaded rod, cut to length |
| M20 | 2.5 | Fully threaded | 1000/2000/3000 | DIN 975 | Fully threaded rod, cut to length |
| M24 | 3.0 | Fully threaded | 1000/2000/3000 | DIN 975 | Fully threaded rod, cut to length |
| M30 | 3.5 | Fully threaded | 1000/2000/3000 | DIN 975 | Fully threaded rod, cut to length |
Companion Standards
DIN 939 controls only the geometry of studs & threaded rods. 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 939
DIN 939 is still widely used in European mechanical engineering and as a cross-reference on legacy drawings; its ISO equivalent is preferred for new designs.