ISO 8744:1997

Overview

ISO 8744:1997 specifies the characteristics of full-length taper grooved pins - metallic fasteners with three equally spaced longitudinal grooves - intended for use as press-fit pins. The standard covers pins made of steel and austenitic stainless steel (grade A1) with nominal diameters from 1.5 mm to 25 mm. The displaced material at the grooves produces an expanded diameter that provides a non-positive locking fit when the pin is pressed into a drilled hole of nominal diameter (tolerance H11).

Key topics and requirements

• Pin form and material
  • Full-length, taper grooved pins with three longitudinal grooves.
  • Materials: steel or austenitic stainless steel (A1).
• Dimensional range
  • Nominal diameters: 1.5 mm to 25 mm; lengths and detailed dimensions given in the standard’s table and figure.
• Mechanical properties
  • Hardness ranges stated: steel ~125–245 HV30; austenitic stainless (A1) ~210–280 HV30 (see ISO 3506-1 reference).
  • Minimum double shear strengths are specified (see standard table).
• Fit and installation
  • Expanded diameter (d2) is larger than nominal diameter (d1), producing a non-positive locking fit in an H11 hole.
  • GO/NO-GO ring gauge recommended for checking expanded diameter.
• Surface finish and coatings
  • Steel: plain or with protective coatings (preferred: black oxide, phosphate conversion ISO 9717, or zinc plating with chromate conversion ISO 4042); tolerances apply prior to plating/coating.
  • Stainless: plain natural finish unless otherwise agreed.
• Testing and acceptance
  • Shear strength test per ISO 8749.
  • Acceptance inspection per ISO 3269.
• Designation examples
  • Steel: “Grooved pin ISO 8744 – 6 · 50 – St”
  • Stainless A1: “Grooved pin ISO 8744 – 6 · 50 – A1”

Applications and users

ISO 8744:1997 is used by:

• Fastener and component manufacturers for design and production control.
• Mechanical designers and fit engineers specifying press-fit pins for assemblies.
• Quality, inspection, and procurement teams ensuring conformity to dimensional, hardness, and shear requirements. Practical uses include any assembly requiring a grooved press-fit pin for positional locking, locating, or shear-transmitting connections where controlled expanded diameter and material properties are required.

Related standards

• ISO 3269 - Fasteners: Acceptance inspection
• ISO 3506-1 - Corrosion-resistant stainless steel fasteners (reference for A1)
• ISO 4042 - Fasteners: Electroplated coatings (referenced)
• ISO 8749 - Pins and grooved pins: Shear test
• ISO 9717 - Phosphate conversion coatings

Keywords: ISO 8744:1997, grooved pins, full-length taper grooved pins, fasteners, expanded diameter, shear strength, H11 fit, steel pins, stainless steel pins.