ISO 3315:2018

Overview

ISO 3315:2018 - "Assembly tools for screws and nuts - Driving parts for hand‑operated square drive socket wrenches - Dimensions and tests" defines dimensional and mechanical requirements for the driving parts used with hand‑operated square‑drive socket wrenches. The standard covers common driving parts listed in ISO 1703 (sliding T‑handles, cranks, ratchets, extension bars, hinged handles, bent handles, etc.) and specifies overall dimensions, hardness, torque/torsion test methods, minimum torsional strength values, designation and marking.

Key topics and technical requirements

• Dimensions: Overall dimensional limits for each tool type and nominal square‑drive size are provided (see Table 1). These ensure interchangeability and fit with standardized socket tools.
• Driving square hardness: Driving squares must comply with ISO 1174‑1 and have a minimum Rockwell hardness of 39 HRC.
• Torque/torsion testing method: The test requires inserting the tool into a female test square and applying the specified torque slowly and without shock to the minimum test value. The test mandrel should match the minimum female square size with tolerance H8 and have a minimum hardness of 55 HRC.
• Torsional strength and endurance: Minimum torsional strength values and special test conditions are specified per tool type. For ratchets, an endurance test of 50,000 cycles at defined torques (table values vary by square size) and a typical frequency of 30 cycles/min is required; no maintenance is allowed during the test and all teeth must be exercised.
• Specific loading instructions: The standard prescribes where to apply load for each tool type (e.g., at handle end for sliding T‑handle, mid‑hand area for crank, near end for ratchet) and requires ratchet reversible tests in both directions.
• Designation and marking: Conforming parts must be designated by tool name + "ISO 3315" + square size (mm) and permanently marked with the manufacturer’s name or trademark.

Applications and users

• Who uses it: Manufacturers of hand tools, quality engineers, product designers, test laboratories, procurement/specification writers, and standards compliance teams.
• Practical value:
  • Ensures compatibility of driving parts and sockets across suppliers.
  • Provides test procedures for validating torsional strength, durability and safety of socket wrenches and accessories.
  • Supports product certification, quality control, and procurement specifications for industrial, automotive, maintenance and assembly applications.

Related standards

• ISO 1703 - Nomenclature for assembly tools for screws and nuts (references covered parts)
• ISO 1174‑1 - Driving squares for hand tools (dimensional / interface requirements)
• ISO 1711‑1 - Technical specifications for torque values (referenced for torque series)

Keywords: ISO 3315:2018, driving parts, hand‑operated square drive socket wrenches, dimensions and tests, Rockwell hardness, torsional strength, torque testing, endurance test.