ISO 8734 is the governing dimensional standard for dowel pins. 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 8734 — Scope
ISO 8734 specifies the dimensions and tolerances of dowel pins. 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
ISO 8734, alongside the related ISO 8734 / DIN 6325 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 ISO 8734
| Nominal diameter (mm) | Diameter tolerance | Common length range (mm) | Material | Hardness | Reference standard | Notes |
|---|---|---|---|---|---|---|
| 1.0 | h6 | 4~10 | Alloy steel | Hardened | ISO 8734 / DIN 6325 | Both ends chamfered, precision fit |
| 1.2 | h6 | 4~12 | Alloy steel | Hardened | ISO 8734 / DIN 6325 | Both ends chamfered, precision fit |
| 1.5 | h6 | 4~16 | Alloy steel | Hardened | ISO 8734 / DIN 6325 | Both ends chamfered, precision fit |
| 2.0 | h6 | 6~20 | Alloy steel | Hardened | ISO 8734 / DIN 6325 | Both ends chamfered, precision fit |
| 2.5 | h6 | 6~24 | Alloy steel | Hardened | ISO 8734 / DIN 6325 | Both ends chamfered, precision fit |
| 3.0 | h6 | 8~30 | Alloy steel | Hardened | ISO 8734 / DIN 6325 | Both ends chamfered, precision fit |
| 4.0 | h6 | 8~40 | Alloy steel | Hardened | ISO 8734 / DIN 6325 | Both ends chamfered, precision fit |
| 5.0 | h6 | 10~50 | Alloy steel | Hardened | ISO 8734 / DIN 6325 | Both ends chamfered, precision fit |
| 6.0 | h6 | 12~60 | Alloy steel | Hardened | ISO 8734 / DIN 6325 | Both ends chamfered, precision fit |
| 8.0 | h6 | 16~80 | Alloy steel | Hardened | ISO 8734 / DIN 6325 | Both ends chamfered, precision fit |
| 10.0 | h6 | 20~100 | Alloy steel | Hardened | ISO 8734 / DIN 6325 | Both ends chamfered, precision fit |
| 12.0 | h6 | 25~120 | Alloy steel | Hardened | ISO 8734 / DIN 6325 | Both ends chamfered, precision fit |
| 16.0 | h6 | 30~160 | Alloy steel | Hardened | ISO 8734 / DIN 6325 | Both ends chamfered, precision fit |
| 20.0 | h6 | 35~200 | Alloy steel | Hardened | ISO 8734 / DIN 6325 | Both ends chamfered, precision fit |
| 25.0 | h6 | 45~200 | Alloy steel | Hardened | ISO 8734 / DIN 6325 | Both ends chamfered, precision fit |
| 30.0 | h6 | 50~200 | Alloy steel | Hardened | ISO 8734 / DIN 6325 | Both ends chamfered, precision fit |
| 40.0 | h6 | 60~200 | Alloy steel | Hardened | ISO 8734 / DIN 6325 | Both ends chamfered, precision fit |
| 50.0 | h6 | 80~200 | Alloy steel | Hardened | ISO 8734 / DIN 6325 | Both ends chamfered, precision fit |
Companion Standards
ISO 8734 controls only the geometry of dowel pins. 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 ISO 8734
Choose ISO 8734 for international engineering work and OEM supply where ISO standards are the contractual reference. It is the default modern specification for dowel pins.

