Square Head Bolts with Collar manufactured to DIN 478 are dimensioned by the size table reproduced on this page. The standard fixes geometry and tolerances only; material and property class are assigned by separate documents, and surface finish by separate finish standards.
DIN 478 — Scope
DIN 478 is "Square head bolts with collar".
Material, property class, surface finish and packaging are governed by separate documents — ISO 898-1 and ISO 898-2 for mechanical property classes, ISO 4042 for electroplated finishes.
Tolerance & Product Grades
DIN 478 does not divide square head bolts with collar into product grades. Tolerances are given as limits on the individual dimensions in the table.
Where a general-tolerance class is cited on the drawing instead, it applies to the dimensions not otherwise toleranced.
Dimensions Specified by DIN 478
| Size | Pitch P (mm) | b1 (mm) | b2 (mm) | c (mm) | da (mm) | dc (mm) | Width across corners e (mm) | Head height k (mm) | r (mm) | Width across flats s (mm) | Length range l (mm) | Reference standard |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| M5 | 0.8 | 16 | 16 | 2 | 5.7 | 9.5 | 6.5 | 7 | 0.25 | 5 | 10~30 | DIN 478 |
| M6 | 1 | 18 | 18 | 2 | 6.8 | 10.5 | 8 | 8 | 0.25 | 6 | 10~40 | DIN 478 |
| M8 | 1.25 | 22 | 22 | 2 | 9.2 | 13.5 | 10 | 10 | 0.4 | 8 | 16~45 | DIN 478 |
| M10 | 1.5 | 26 | 32 | 3 | 11.2 | 16.5 | 13 | 13 | 0.4 | 10 | 20~60 | DIN 478 |
| M12 | 1.75 | 30 | 36 | 3 | 13.7 | 19.5 | 17 | 15 | 0.6 | 13 | 25~90 | DIN 478 |
| M16 | 2 | 38 | 44 | 4 | 17.7 | 25 | 22 | 20 | 0.6 | 17 | 30~140 | DIN 478 |
| M20 | 2.5 | 45 | 52 | 5 | 22.4 | 31 | 28 | 25 | 0.8 | 22 | 35~180 | DIN 478 |
| M24 | 3 | 54 | 60 | 6 | 26.4 | 36 | 32 | 28 | 0.9 | 24 | 35~180 | DIN 478 |
Equivalent Standards
Where direct equivalents exist (ISO ↔ DIN, ISO ↔ ASME), they are listed on the parent Square Head Bolts with Collar page.
Always confirm against the dimensions on this page, since some "equivalent" standards differ in tolerances and head geometry.
When to Specify DIN 478
DIN 478 is still widely used in European mechanical engineering and as a cross-reference on legacy drawings; its ISO equivalent is preferred for new designs.
Custom manufacturing · Made to drawing
Need a bolt to this standard in a non-standard size?
Parts built to DIN 478 are already in the catalog, so a special is usually a variation on existing tooling rather than a new design — which is what keeps the cost down. Made by cold heading or hot forging.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
