ISO 2725-2:2017

Overview

ISO 2725-2:2017 - "Assembly tools for screws and nuts - Square drive sockets - Part 2: Machine-operated sockets ('impact')" specifies the dimensions, designation and marking requirements for machine-operated (impact) square drive sockets whose operating end is hexagonal or bi‑hexagonal in accordance with ISO 1174‑2. It covers square drive sizes from 6.3 to 40 mm and defines retaining pin and retaining ring dimensions. This edition (2017) focuses on geometric and identification requirements; technical performance specifications are provided separately in ISO 1711‑2.

Key topics and requirements

• Scope: Applies to machine‑operated “impact” square drive sockets with hex or bi‑hex operating ends (see ISO 1174‑2).
• Dimensions: Detailed dimension tables (Tables 1–6) in millimetres for multiple square drive sizes (6.3 → 40). Figures are illustrative and not prescriptive for design.
• Tolerances: Width‑across‑flats tolerances conform to ISO 691; manufacturers may choose deviation series.
• Retaining hardware: Dimensions for retaining pins and retaining rings are provided (Tables 7–8).
• Designation: Mandatory format includes form (Hex or Bi‑hex), reference to ISO 2725‑2, square drive size and width‑across‑flats (example: “Bi‑hex impact socket ISO 2725‑2, 12.5 × 10”).
• Marking: Sockets must be permanently and legibly marked with at least the manufacturer’s name or trademark and the width across flats.
• Notes: Clause on technical specifications was removed (refer to ISO 1711‑2). Guide‑ways for certain drive forms are at manufacturers’ discretion.

Practical applications and who uses this standard

ISO 2725‑2 is essential for:

• Tool manufacturers designing and producing machine‑operated impact sockets to ensure interchangeability and correct fit.
• OEMs and assemblers specifying sockets for powered tools on production lines (automotive, heavy machinery, aerospace, industrial assembly).
• Procurement and quality assurance teams requiring consistent designation, markings and dimensional conformity across suppliers.
• Standards and compliance engineers harmonizing product documentation with ISO nomenclature and reference chains.
• Aftermarket tool suppliers and maintenance departments selecting replacement sockets or specifying retaining pins/rings.

Benefits include improved tool compatibility, reduced assembly errors, and clearer product identification for supply chains and maintenance.

Related standards

• ISO 1174‑2 - Driving squares for power socket tools (operating end forms referenced).
• ISO 1711‑2 - Technical specifications for machine‑operated sockets (performance & material requirements).
• ISO 691 - Tolerances for wrench and socket openings.
• ISO 272, ISO 4014, ISO 4032 - Related hexagon dimensions and fastener references.

Keywords: ISO 2725-2:2017, machine‑operated impact square drive sockets, square drive dimensions, socket designation, socket marking, ISO 1174‑2, ISO 1711‑2.