NAS75-3-009 – Plain Press-Fit Bushing (Aluminum Bronze)
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The NAS75-3-009 is a flight-critical, plain press-fit bushing manufactured in strict accordance with National Aerospace Standard NAS75. This headless sleeve bearing is engineered to provide a precise, replaceable wear surface in structural joints subjected to rotational or oscillating motion around a fastener, typically a bolt or pin. Its primary function is to protect the more expensive or structurally integral surrounding components (e.g., control surface hinges, landing gear linkages, actuator fittings) from wear and elongation, ensuring the longevity and integrity of the assembly.
Fabricated from high-strength Aluminum Bronze alloy (typically AMS 4640), the NAS75-3-009 is selected for its excellent bearing properties, high strength, and corrosion resistance. It is designed to be installed with a significant interference fit into a precisely reamed hole, ensuring it remains securely fixed within the housing. The inner diameter is precision-machined to provide a close-tolerance running fit for the mating pin or bolt. As a fundamental component in managing wear and maintaining joint integrity, the use of a certified NAS75 bushing is essential for airworthiness.
Key Features
National Aerospace Standard (NAS) Certified: Guarantees adherence to stringent material, dimensional, tolerance, and quality requirements.
Aluminum Bronze Construction (AMS 4640): Offers an excellent combination of high strength, wear resistance, corrosion resistance, and anti-galling bearing properties.
Headless Press-Fit Design: Provides a secure, fixed installation within the housing via a controlled interference fit, preventing rotation and migration.
Replaceable Wear Surface: Acts as a sacrificial element, protecting the primary structural components from costly wear and damage.
Precision Machined Tolerances: Ensures accurate inner and outer diameters for proper installation fit and correct running clearance with the mating fastener.
Technical Specifications
Part Number: NAS75-3-009
Component Type: Bushing, Plain, Press Fit, Headless
Governing Specification: NAS75
Material: Aluminum Bronze (typically C63000 per AMS 4640).
Finish: Natural (as machined).
Dimensions:
Nominal Inside Diameter (ID): 0.1875 inches (3/16")
Outside Diameter (OD): 0.3125 inches (5/16")
Length (L): 0.2812 inches (9/32")
Installation: Press Fit (Requires specific interference fit with housing bore).
Aircraft Compatibility
The NAS75-3-009 is a standard hardware component used across all categories of certified aircraft from all major manufacturers (e.g., Textron, Boeing, Airbus, Lockheed Martin, Piper). It is specified in countless articulating joints throughout the airframe.
Crucial Note: The correct bushing part number for a specific application must be verified against the aircraft's Illustrated Parts Catalog (IPC) or maintenance manual.
Applications
This bushing is designed for moderate load, moderate speed rotational or oscillating applications where a precise fit and wear resistance are required. Common uses include:
Flight Control Surface Hinge Points (ailerons, elevators, rudder, flaps)
Landing Gear Linkages, Trunnions, and Pivot Points
Actuator Attachment Fittings
Door Hinge Mechanisms
Engine Control Linkages
Why Choose NAS75-3-009?
Choosing a genuine NAS75-3-009 bushing is a critical decision for ensuring the integrity and longevity of aircraft structural joints. The NAS standard guarantees the correct high-strength Aluminum Bronze alloy, which provides superior wear resistance compared to softer materials. It also guarantees the precise dimensional tolerances required for a proper interference fit; an improper fit can lead to the bushing spinning in its housing (causing damage) or insufficient support for the bolt (leading to joint failure). Using a non-certified bushing risks premature wear, joint sloppiness, or structural failure. This certified part provides a cost-effective way to manage wear by replacing the bushing rather than the entire expensive component it protects.
The NAS75-3-009 operates under principles of tribology as a plain bearing. Its function relies on establishing a lubricant film (typically grease applied during assembly and periodic maintenance) between the inner diameter of the bushing and the rotating/oscillating bolt or pin. In ideal conditions, this creates a state of hydrodynamic or boundary lubrication, preventing direct metal-to-metal contact. The Aluminum Bronze (C63000) material is specifically chosen for this role due to its favorable bearing characteristics: high compressive strength to support the load, good thermal conductivity to dissipate frictional heat, inherent resistance to galling and seizure against steel fasteners, and the ability to embed small contaminant particles, reducing abrasive wear. The critical interference fit achieved during installation is essential not only to retain the bushing but also to prevent fretting corrosion between the bushing's outer diameter and the housing bore, which can occur due to micro-movements under cyclic loading if the fit is loose.
Note: This is a flight-critical structural component. Installation requires specialized tooling (e.g., an arbor press with appropriately sized installation mandrels) to ensure the bushing is pressed in straight and without damage. The housing bore must be precisely reamed or honed to the correct dimension specified in the maintenance manual to achieve the required interference fit. After installation, the inner diameter of the bushing typically requires reaming to achieve the final, precise running clearance for the mating bolt or pin. Consult the applicable maintenance manual for lubrication requirements.
Documentation
The definitive technical requirements for this component are detailed in National Aerospace Standard NAS75. These proprietary documents must be sourced directly from the relevant standards organizations for complete engineering specifications.