ISO 1711-2:2019

Overview

ISO 1711-2:2019 specifies the hardness and minimum torsional strength requirements for machine-operated square-drive sockets intended for use with impact wrenches (see ISO 2725-2). The standard defines material, heat-treatment and test procedures that ensure sockets deliver reliable, safe performance under torsional loading and are compatible with standard driving squares and hexagon test mandrels.

Key procedural elements covered by the standard include hardness testing (ISO 6508-1), torsion torque testing, and engagement requirements for the test mandrel. The document focuses on torsional testing and related hardness limits to provide a practical method to assess socket durability for impact applications.

Key Topics

• Scope and applicability

  • Machine-operated square-drive impact sockets per ISO 2725-2.
  • Applies to sockets intended for use with impact wrenches.

• Materials and heat treatment

  • Sockets, driving squares and accessories shall be manufactured from steel and heat treated to meet the specified hardness and torsional requirements.

• Hardness requirements

  • Hardness testing is carried out in accordance with ISO 6508-1 (Rockwell method).
  • Rockwell hardness ranges are specified by driving square nominal sizes and width-across-flats values (see standard tables).

• Torsion torque testing

  • Empirical formulae and tabulated minimum test torsion torques are provided (Table 1 and Table 3 in the standard).
  • Test method requires full engagement of the socket on a hardened hexagon test mandrel and application of the minimum test torsion torque.
  • After testing, any deformation shall not affect the usability of the socket.

• Test mandrel and geometry

  • Test mandrel dimensions (across-flats, across-corners and mandrel height) and chamfer angle are specified; chamfer angle α shall be between 15° and 30°.
  • Mandrel hardness: not less than 55 HRC for nominal widths ≤ 22 mm, and not less than 50 HRC for nominal widths ≥ 24 mm (per clause 5.2).
  • Mandrel tolerance requirements (h8) and coaxial alignment of axes during the test are required.

Applications

ISO 1711-2:2019 is used by manufacturers, test laboratories and quality engineers to:

• Validate design and heat-treatment processes for impact sockets.
• Verify torsional strength and durability before commercial release.
• Ensure compatibility with impact wrenches and driving squares in industrial and maintenance settings.

Benefits include improved product safety, predictable service life under torsional loads, and harmonized test methods for regulatory and procurement requirements.

Related Standards

• ISO 2725-2 - Square drive sockets - Part 2: Machine-operated sockets (impact)
• ISO 691 - Wrench and socket openings - Tolerances for general use
• ISO 6508-1 - Rockwell hardness test - Test method
• ISO 1174-2 and ISO 1703 referenced for driving square dimensions and nomenclature

For implementation, consult the full ISO 1711-2:2019 text and the referenced tables for exact torque values, hardness ranges and mandrel dimensions.