ISO 8744:2025

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

• ISO 13669 - Fasteners - Grooved pins - General requirements
• ISO 3506-6 - Stainless steel fastener material rules
• ISO 4042, ISO 10683, ISO 9717, ISO 16048 - Coatings and surface treatments
• ISO 3269, ISO 1891-4 - Inspection and lot identification
• Other grooved-pin product standards: ISO 8739, ISO 8740–8747, ISO 13670, ISO 13672

Keywords: ISO 8744, taper grooved pins, full-length progressive grooves, fasteners, expanded diameter, pull-out resistance, stainless steel pins, fastener standards.