For split cotter pins, ISO 1234 is the governing document for the dimensions listed below. Mechanical and performance requirements for this part family are set by its own standards, not by the bolt and screw property-class documents.
ISO 1234 — Scope
ISO 1234 specifies the dimensional requirements for split cotter pins. Material, surface condition and any performance rating are set by separate documents specific to this part family — ISO 898-1 and ISO 898-2, which govern bolt and nut property classes, do not apply here.
Tolerance & Product Grades
Tolerances for split cotter pins are given as limits on the individual dimensions in the table rather than as a fastener product grade. Where a general-tolerance class is cited on the drawing instead, it applies to the dimensions not otherwise toleranced.
Dimensions Specified by ISO 1234
| Nominal diameter (mm) | Hole dia min (mm) | Hole dia max (mm) | Common length range (mm) | Material | Reference standard |
|---|---|---|---|---|---|
| 0.6 | 0.7 | 0.9 | 6~16 | Low-carbon steel / stainless | ISO 1234 / DIN 94 |
| 0.8 | 0.9 | 1.1 | 6~20 | Low-carbon steel / stainless | ISO 1234 / DIN 94 |
| 1.0 | 1.1 | 1.3 | 8~25 | Low-carbon steel / stainless | ISO 1234 / DIN 94 |
| 1.2 | 1.3 | 1.5 | 8~30 | Low-carbon steel / stainless | ISO 1234 / DIN 94 |
| 1.6 | 1.7 | 1.9 | 10~40 | Low-carbon steel / stainless | ISO 1234 / DIN 94 |
| 2.0 | 2.1 | 2.4 | 12~50 | Low-carbon steel / stainless | ISO 1234 / DIN 94 |
| 2.5 | 2.7 | 3.0 | 14~63 | Low-carbon steel / stainless | ISO 1234 / DIN 94 |
| 3.2 | 3.4 | 3.8 | 18~80 | Low-carbon steel / stainless | ISO 1234 / DIN 94 |
| 4.0 | 4.3 | 4.8 | 22~100 | Low-carbon steel / stainless | ISO 1234 / DIN 94 |
| 5.0 | 5.4 | 5.9 | 25~125 | Low-carbon steel / stainless | ISO 1234 / DIN 94 |
| 6.3 | 6.7 | 7.4 | 32~160 | Low-carbon steel / stainless | ISO 1234 / DIN 94 |
| 8.0 | 8.5 | 9.3 | 40~200 | Low-carbon steel / stainless | ISO 1234 / DIN 94 |
| 10.0 | 10.6 | 11.5 | 50~250 | Low-carbon steel / stainless | ISO 1234 / DIN 94 |
| 13.0 | 13.8 | 14.9 | 63~315 | Low-carbon steel / stainless | ISO 1234 / DIN 94 |
Equivalent Standards
Where direct equivalents exist (ISO ↔ DIN, ISO ↔ ASME), they are listed on the parent Split Cotter Pins page. Always confirm against the dimensions on this page, since some "equivalent" standards differ in tolerances and head geometry.
When to Specify ISO 1234
Choose ISO 1234 for international engineering work and OEM supply where ISO standards are the contractual reference. It is the default modern specification for split cotter pins.
