Overview
ISO 8749:1986 - Pins and grooved pins - Shear test defines a standardized test method for determining the shear resistance of metallic pins and grooved (elastic) pins with nominal diameters from 0.8 mm to 25 mm inclusive. The standard specifies the test principle, a typical test fixture, specimen mounting, test speed, and acceptance observations so results are repeatable and comparable across laboratories and manufacturers.
Key topics and requirements
- Scope: Metallic pins and grooved (cannelée / elastic) pins, nominal diameter 0.8–25 mm.
- Test principle: Apply a shear load (typically double shear fixture) and record the maximum load at rupture - this is the pin’s double-shear resistance.
- Fixture details:
- Typical test fixture (figure provided) with support blocks and load block drilled for the pin nominal diameter (hole tolerance H6).
- Mounting sleeves and shear blocks are hardened; block hardness must be at least 700 HV.
- Clearance (play) between support block and load block must not exceed 0.15 mm.
- Shear plane geometry:
- Each shear plane located at least one pin diameter from the corresponding pin end.
- Distance between the two shear planes must be at least two times the pin diameter.
- Pins too short for double shear are tested in pairs in single shear, loaded simultaneously.
- Special mounting: Elastic (grooved) pins are mounted with the slot facing upwards in the fixture.
- Test procedure and acceptance:
- Pins are tested to rupture; the maximum applied load at rupture (or just before) is reported as shear strength.
- Pins should display ductile shear without longitudinal cracking.
- Test crosshead speed must not exceed 13 mm/min.
Applications and users
ISO 8749:1986 is used to:
- Verify mechanical performance and quality of pins and grooved pins in manufacturing QA/QC.
- Provide comparative shear strength data for design and material selection (mechanical engineers, design engineers).
- Support procurement specifications and acceptance testing for fasteners in automotive, aerospace, machinery and general engineering.
- Standardize test reporting in independent test laboratories and certification bodies.
Typical users: fastener manufacturers, test laboratories, quality engineers, design and R&D teams, and standards/inspection authorities.
Related standards
- Developed by ISO Technical Committee ISO/TC 2 (fasteners). For comprehensive fastener testing and specification, consult other ISO standards on pins, fasteners and mechanical test methods issued by ISO/TC 2 (refer to the latest editions).
