ISO 4014 is the governing dimensional standard for hex bolt. This page sets out the scope of the standard, reproduces the full size table it specifies, and lists the DIN/ISO/ASME cross-references commonly cited in datasheets and drawings.
ISO 4014 — Scope
ISO 4014 is "Fasteners — Hexagon head bolts — Product grades A and B". It covers M1.6 to M64. Partly threaded. The fully threaded equivalent is ISO 4017.
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
ISO 4014 defines product grades A and B. The grade sets how closely the finished part has to follow the nominal dimensions; it is not a strength rating.
Dimensions Specified by ISO 4014
| Size | Pitch (mm) | Nominal diameter d (mm) | Length L (mm) | Width across flats s (mm) | Width across corners e (mm) | Head height k (mm) |
|---|---|---|---|---|---|---|
| M3 | 0.5 | 3 | 20 | 5.5 | 6.01 | 2.0 |
| M4 | 0.7 | 4 | 25 | 7.0 | 7.66 | 2.8 |
| M5 | 0.8 | 5 | 30 | 8.0 | 8.79 | 3.5 |
| M6 | 1.0 | 6 | 40 | 10.0 | 11.05 | 4.0 |
| M8 | 1.25 | 8 | 50 | 13.0 | 14.38 | 5.3 |
| M10 | 1.5 | 10 | 60 | 16.0 | 17.77 | 6.4 |
| M12 | 1.75 | 12 | 80 | 18.0 | 20.03 | 7.5 |
| M14 | 2.0 | 14 | 80 | 21.0 | 23.36 | 8.8 |
| M16 | 2.0 | 16 | 100 | 24.0 | 26.75 | 10.0 |
| M18 | 2.5 | 18 | 100 | 27.0 | 30.14 | 11.5 |
| M20 | 2.5 | 20 | 120 | 30.0 | 33.53 | 12.5 |
| M24 | 3.0 | 24 | 150 | 36.0 | 39.98 | 15.0 |
| M30 | 3.5 | 30 | 180 | 46.0 | 50.85 | 18.7 |
| M36 | 4.0 | 36 | 200 | 55.0 | 60.79 | 22.5 |
Companion Standards
ISO 4014 controls only the geometry of hex bolt — gb/t 5782 / iso 4014 (series 006). The mechanical strength is set by ISO 898-1 (bolts, screws and studs) or ISO 898-2 (nuts); the surface finish is governed by separate finish standards such as ISO 4042 for electroplating. For corrosion testing, the relevant document is ISO 9227 (neutral salt spray).
When to Specify ISO 4014
Choose ISO 4014 for international engineering work and OEM supply where ISO standards are the contractual reference. It is the default modern specification for hex bolt — gb/t 5782 / iso 4014 (series 006).
Custom manufacturing · Made to drawing
Need a bolt to this standard in a non-standard size?
Parts built to ISO 4014 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.
