Overview
ISO 8748:2007 specifies the characteristics of coiled, heavy duty spring-type straight pins (spring pins) made of steel or of austenitic or martensitic stainless steel. The standard covers nominal diameters from 1.5 mm to 20 mm inclusive and defines dimensional ranges, material and hardness requirements, testing and acceptance criteria, and marking/ designation. ISO 8748:2007 is intended for manufacturers, designers and quality inspectors dealing with heavy-duty coiled spring pins used in mechanical assemblies.
Key topics and requirements
- Dimensions and tolerances: Nominal diameters d = 1.5–20 mm; detailed maximum/minimum diameters and nominal lengths (commercial lengths from small sizes up to 200 mm and beyond, with steps above 200 mm) are defined in the standard.
- Hole fit: The mating hole diameter shall equal the pin nominal diameter and conform to tolerance class H12 (ISO 286-2).
- Materials and metallurgy: Pins may be manufactured from carbon steel, austenitic or martensitic stainless steel; chemical composition limits are specified for different material groups.
- Hardness: Vickers hardness requirements are specified (hardness testing per ISO 6507-1). Typical Vickers ranges for the applicable material conditions are included in the standard.
- Mechanical testing: Shear strength tests are required and shall be performed in accordance with ISO 8749. Acceptance inspection follows ISO 3269.
- Surface finish and coatings: Pins are normally supplied plain with a protective lubricant. The standard warns about hydrogen embrittlement risks: electroplating or phosphate coating is discouraged unless mitigation measures (post-plating baking per ISO 4042) are applied.
- Workmanship: Pins must be free of detrimental defects and burrs.
Applications
ISO 8748 spring pins are used wherever a resilient, heavy-duty coiled pin is required to:
- Retain components on shafts or in bores
- Provide shear protection or alignment in assemblies
- Serve as a removable mechanical fastener in machinery, automotive and industrial equipment
The standard helps ensure interchangeability, reliable shear performance, and corrosion resistance for heavy-duty coiled spring pins.
Who should use this standard
- Fastener and spring-pin manufacturers
- Mechanical design engineers specifying retaining or shear pins
- Procurement/specification writers requiring standardized parts (ISO 8748:2007)
- Quality and inspection personnel performing acceptance testing
Designation examples
- Spring pin ISO 8748 - 6 × 30 - St (steel)
- Spring pin ISO 8748 - 6 × 30 - A (austenitic stainless steel)
Related standards
Keywords: ISO 8748:2007, spring-type straight pins, coiled heavy duty, spring pins, stainless steel pins, shear strength, Vickers hardness, H12 tolerance.
