ISO 11926-1:1995

Overview

ISO 11926-1:1995 specifies the dimensional requirements, test methods and designation for ports with inch threads (ISO 725) that use an O-ring seal in a truncated housing. This part of ISO 11926 is intended for general use and fluid-power applications (hydraulic and pneumatic) and forms the port-side specification for mating stud ends described in ISO 11926-2 and ISO 11926-3.

Key practical points in the standard include the recommended port geometry, surface finish guidance, and the recommended identification phrase manufacturers should use when declaring conformity.

Key Topics

• Port dimensions and tolerances: Ports are defined to match ISO 725 inch threads and include detailed dimensional tables for commonly used thread sizes and corresponding countersink and depth dimensions.
• O-ring sealing in truncated housing: Specifies the housing geometry required to retain an O-ring seal reliably during assembly and operation.
• Test methods: Ports must be tested with mating male elements according to the methods prescribed in ISO 11926-2 and ISO 11926-3.
• Designation and identification: The standard recommends a clear identification phrase for documentation and commercial literature: "Orifices conforming to ISO 11926-1:1995 - Ports with O-ring seal in a truncated housing."
• Pressure guidance: The standard notes allowable working pressures, for example up to 63 MPa (630 bar) for non-orientable male elements and up to 40 MPa (400 bar) for orientable male elements, subject to material, size and design considerations.

Applications

This standard is directly applicable to designers, manufacturers and maintenance engineers working with:

• Hydraulic pumps, motors, valves, actuators and manifolds where fluid-power connections require reliable static sealing.
• Pneumatic systems in industrial automation where O-ring sealed ports provide compact, reusable connections.
• Equipment catalogues, test reports and procurement documentation where standardized port designation and interchangeability are required.

Benefits of applying ISO 11926-1:1995 include improved interchangeability between components, predictable sealing performance when paired with compatible stud ends, and a common basis for dimensional inspection and acceptance testing.

Related Standards

• ISO 11926-2:1995 - Stud ends (heavy series S) and test prescriptions.
• ISO 11926-3:1995 - Stud ends (light series L) and test prescriptions.
• ISO 725 - Inch thread basic dimensions (threads used by these ports).
• ISO 2306 - Drills for tapping preparation referenced for pilot hole sizes.
• ISO 5598 - Vocabulary for hydraulic and pneumatic terms.

Adopting ISO 11926-1:1995 ensures compatibility with the broader ISO series for fluid-power ports and fittings, enabling reliable design, testing and procurement across hydraulic and pneumatic systems.