Overview
ISO 1173:2001 specifies the dimensions and torque testing requirements for drive ends used with hand- and machine-operated screwdriver bits and the connecting parts (tool holders, driving spindles). The standard defines a set of distinctive drive-end forms (A–H) - male and female hexagon and flat end types - and provides the dimensional tables, designation rules and minimum torque test requirements to ensure interchangeability of bits and tool holders.
Keywords: ISO 1173:2001, drive ends, screwdriver bits, torque testing, dimensions, interchangeability, hexagon, flat end.
Key topics and technical requirements
- Drive-end forms and dimensions: Forms A–H cover male/female hexagon and flat end geometries with nominal dimensions given in Tables 1–8. Figures illustrate profile and groove options; unspecified details are left to the user.
- Designation: Drive ends are designated by type, ISO reference, form letter and nominal dimension (e.g., Male hexagon ISO 1173 - A 3).
- Torque testing:
- Test pieces must match counterbodies in dimension and have a hardness of at least HRC 62.
- Test torque values are provided in Table 9 for each nominal dimension/form. (Example: for flat-end Forms G/H with a nominal dimension of 7 mm the test torque is 25 N·m.)
- Connecting parts for which the torque values apply are intended to be made of alloyed or tool steel, hardened and tempered or heat treated to at least HRC 53.
- Tests require full engagement over the specified lengths and the torque must be applied smoothly; parts must show no permanent deformation, cracks or fractures that affect usability.
- Design notes: Retaining system details (balls, grooves, snap rings) and some groove shapes are left to the manufacturer; magnetic screwdriver bits may omit certain bores/grooves.
Applications
ISO 1173 is directly relevant for:
- Manufacturers of screwdriver bits, bit holders and machine driving spindles designing to standardized drive ends.
- Tool designers and mechanical engineers specifying tool interfaces for assembly equipment.
- Quality control, testing laboratories and procurement teams verifying dimensional conformity and mechanical strength (torque) of connecting parts.
- OEMs in automotive, electronics and industrial assembly where tool and bit interchangeability and reliable torque transmission are critical.
Related standards and committees
- Prepared by ISO/TC 29 (Small tools), Subcommittee SC 10 (Assembly tools). For broader context consult other ISO standards on assembly tools and tooling interfaces produced by the same technical committee.
This standard supports reliable, interchangeable tool interfaces by combining clear dimensional definitions with mechanical (torque) verification - essential for consistent assembly performance in industrial production.
Open preview (PDF)Assembly tools for screws and nuts — Drive ends for hand- and machine-operated screwdriver bits and connecting parts — Dimensions, torque testing
