ISO 413:1974

Overview

ISO 413:1974 specifies geometric and functional requirements for the heads of axial-type lubricating (grease) nipples used on aircraft. The standard defines the allowable envelope/profile for nipple heads, the clearance space required around the nipple to permit access by a lubricating gun, and the operating angle limits for coupling, uncoupling and lubrication without leakage. ISO 413 was prepared by ISO/TC 20 (Aircraft and space vehicles) and replaces ISO Recommendation R 413-1965.

Key topics and technical requirements

• Envelope/profile dimensions: The standard provides the maximum and minimum envelope limits for axial-type nipple heads (illustrated in figure 1 of the document). Tip shape is optional so long as the profile stays within the specified envelope.
• Clearance space: Specifies the clearance that must be provided in the region of the nipple to allow lubricating-gun coupling and operation without obstruction.
• Coupling/uncoupling geometry: Defines the required approach and uncoupling capability for the lubricating gun connector; during coupling/uncoupling the connector may need to be tilted (document notes up to 25° in any radial direction for coupling/uncoupling).
• Operating angle for lubrication: Requires that the nipple tip and connector admit lubricant without leakage when the connector is attached at any angle up to 10° between the connector axis and the nipple tip axis, in any radial direction.
• Illustrative figures: Figure 1 (head profile/envelope) and Figure 2 (connector coupling/uncoupling requirements) support dimensional and functional interpretation.

Applications and users

• Aircraft designers and structural engineers: Ensure component geometry on airframes, landing gear, control surfaces and exposed mechanisms accommodates standard nipple heads and access clearances.
• Maintenance and overhaul organizations: Specify nipple types and installation clearances to enable reliable greasing procedures and prevent leakage.
• Component and fastener manufacturers: Design and produce lubricating nipples and mating lubricating-gun connectors that comply with the envelope, angle, and leakage requirements.
• Regulatory bodies and procurement: Reference ISO 413 in specifications, quality control and acceptance criteria for aircraft equipment and lubrication systems.

Benefits

• Ensures interchangeability and reliable maintenance access across aircraft platforms.
• Reduces risk of leakage and improper lubrication from misaligned connectors.
• Provides clear dimensional requirements to simplify supplier/manufacturer compliance.

Related standards

• ISO 413 supersedes ISO Recommendation R 413-1965. (Prepared by ISO/TC 20: Aircraft and space vehicles.) Organizations should also consult applicable aircraft manufacturer standards and maintenance manuals for installation-specific requirements.