Overview
ISO 8744:2025 specifies the characteristics of taper grooved pins with full-length progressive grooves (closed at the insertion side) made in steel and stainless steel, covering nominal diameters from 1 mm to 25 mm. These grooved pins are engineered to lock two or more parts together with easy installation and high pull-out resistance due to the pin’s elastic-fit behaviour. General functional principles and common requirements for grooved pins and assembly are given in ISO 13669.
Key topics and requirements
- Geometry and grooves
- Full‑length progressive grooves with three grooves; grooves are closed at the insertion end and open at the opposite end.
- Groove angle referenced (≈70°) and groove spacing set at 120° ±20°.
- Rounded (RN) or optional chamfered (CH) ends; grooves must start a specified distance from the end.
- Dimensions and tolerances
- Nominal diameters 1–25 mm; standard length ranges and expanded diameters defined (see Tables 1–2 in the standard).
- Control of expanded diameter (d) and pin straightness (t) per ISO 13669.
- Dimensions apply prior to coating for plated/treated pins.
- Materials and surface condition
- Standard materials: steel (symbol St) and stainless steel grades (A1, A2, A4, C1, F1); other materials (hardened steels, brass, aluminium) may be used by agreement.
- Surface treatments referenced: electroplated coatings (ISO 4042), zinc flake (ISO 10683), phosphate (ISO 9717), passivation (ISO 16048).
- Quality, inspection and labelling
- Acceptance inspection per ISO 3269; lot identification per ISO 1891-4.
- Mandatory package labelling: reference ISO 8744, nominal diameter/length, end option (CH), material symbol, finish, manufacturer ID, lot number, quantity.
- Designation
- Clear designation examples provided (e.g., “Grooved pin ISO 8744 – 6 × 50 – St” or “… – CH – A1”).
Applications and users
ISO 8744 grooved pins are used where a secure, interference‑fit locking pin with high pull‑out resistance and easy assembly is required. Typical users include:
- Mechanical design and assembly engineers specifying fasteners for machinery, automotive, aerospace and industrial equipment
- Fastener manufacturers and suppliers producing or certifying taper grooved pins
- Quality and procurement teams ensuring compliance with international fastener standards
- Maintenance and refurbishment operations needing durable, replaceable locking pins
Related standards
Keywords: ISO 8744, taper grooved pins, full-length progressive grooves, fasteners, expanded diameter, pull-out resistance, stainless steel pins, fastener standards.