Overview
ISO 1858:1977 specifies the dimensional and geometric requirements for general-purpose hubs and reels with a 76 mm (3 in) centre hole intended for magnetic tape used in instrumentation interchange. The standard sets out form, fit and tolerance criteria that promote mechanical compatibility, reliable tape exchange and consistent handling across instrumentation systems and manufacturers.
Key Topics
- Scope and application: Applies to hubs and reels designed for magnetic tape interchange in measurement and instrumentation contexts. It supersedes ISO/R 1858-1971 and was prepared by ISO/TC 97/SC 12.
- Primary dimension: Centre hole (diameter A) nominally 76 mm (3 in) as the reference feature for interchangeability.
- Geometric tolerances: The standard includes limits for parallelism and coaxiality. For example, faces must be parallel to less than 0.0025 mm per millimetre of diameter (or 0.0025 in per inch). Coaxiality limits are specified for core and flange surfaces (examples in the text show runout limits for diameters C and B relative to A).
- Symmetry and construction: Reels and hubs are required to be symmetric so they can be mounted on either side; flanges may include permitted bosses, ribs or reliefs provided they do not extend beyond specified surfaces.
- Optional features: Flange openings and notches to aid tape handling or end-fixing are allowed but not mandatory; their size and placement must remain compatible with interchange requirements.
- Standard widths and tables: The document contains normative tables that list approved widths and dimensional combinations for metal and plastic reels and cores.
Applications
ISO 1858:1977 is intended for:
- Manufacturers of magnetic tape reels and hubs for instrumentation and measurement systems.
- Equipment designers and test houses implementing tape interchange and recording systems.
- Procurement and quality teams requiring consistent mechanical specifications for tape handling and storage.
Key benefits:
- Ensures mechanical interchangeability between media and tape-handling equipment.
- Reduces risk of tape damage and misalignment during exchange and storage.
- Simplifies sourcing and compliance checks across suppliers.
Related Standards
This standard is part of a suite addressing magnetic tape for measurement recording. Related ISO documents referenced or in preparation include:
- ISO 1859 - Blank magnetic tape for measurement recording (dimensional characteristics)
- ISO 1860 - Precision reels for magnetic tape (measurement recording)
- ISO 2690 - Blank magnetic tape (physical properties and test methods)
- ISO 3413 - Tape speeds and track arrangements for measurement recording
- ISO 3615 - Analog recording modes for measurement tape
For implementers, consult ISO 1858:1977 alongside the related series for a complete specification set covering media, reels and test procedures.