AN6-52A – Hexagon Undrilled Fine Thread Aerospace Bolt
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Overview
The AN6-52A is a military-standard, structural airframe bolt, a fundamental component in the construction and repair of certified aircraft, including those manufactured by Textron Aviation. Manufactured in strict accordance with Air Force/Navy (AN) standards, this bolt is engineered to provide reliable, high-strength fastening for a wide range of structural applications. Fabricated from high-tensile strength alloy steel and plated for exceptional corrosion resistance, the AN6-52A is designed to handle the critical shear and tension loads experienced during flight. The "A" suffix in the part number signifies an undrilled shank, indicating it is specifically intended for use with a self-locking nut.
Key Features
- High-Tensile Strength: Fabricated from premium alloy steel (typically 4140 or 8740) and heat-treated to achieve a minimum tensile strength of 125,000 PSI, providing the robust performance required for primary and secondary structural joints.
- Precision Manufacturing: The bolt shank is centerless ground to a precise diameter, and the threads are rolled after heat treatment. This process creates a stronger, more fatigue-resistant fastener compared to bolts with machined or cut threads, which is critical for longevity in a high-vibration environment.
- Corrosion-Resistant Plating: Plated with a durable cadmium finish per specification QQ-P-416, Type II, Class 3. This plating provides excellent protection against environmental corrosion, ensuring the long-term structural integrity of the fastener and the surrounding airframe.
- AN Standard Certified: As a certified AN-standard part, it guarantees full material traceability, dimensional accuracy, and quality control, ensuring it meets the stringent requirements for use in certified aircraft.
Technical Specifications
- Standard: AN6 (Airframe Bolt, Hex Head)
- Full Part Number: AN6-52A
- Material: High-Tensile Alloy Steel
- Finish: Cadmium Plated, Type II, Class 3
- Head Style: Hexagonal (Hex Head)
- Thread Specification: 3/8-24 UNF-3A
- Nominal Diameter: 3/8 inch (0.375 inches)
- Threads Per Inch: 24 (Fine Thread)
- Overall Length: 5-11/32 inches (5.344 inches), measured from under the head.
- Grip Length (Unthreaded Shank): 5-1/8 inches (5.125 inches)
- Drilled Shank: No (Indicated by "A" suffix)
Aircraft Compatibility
The AN6-52A is a universal structural fastener used across nearly every category of certified and experimental aircraft. Its use is specified by the manufacturer's engineering drawings wherever a structural bolt with these precise dimensions is required.
- Common Applications in Textron Aviation Aircraft (Cessna & Beechcraft):
- Airframe Assembly: Joining major structural components like wing spars, fuselage bulkheads, and stringers.
- Engine Mounts: Used in the attachment of engine mount assemblies to the firewall.
- Landing Gear: Securing major components within the landing gear structure.
- Flight Control Systems: Fastening primary flight control bellcranks and brackets.
Applications
The AN6-52A is a workhorse of airframe construction, ideal for creating strong, reliable bolted joints:
- Shear & Tension Joints: Designed to effectively carry both shear (side-to-side) and tension (pulling) loads. The long grip length is essential for passing through thick structural members.
- Use with Self-Locking Nuts: The undrilled "A" designation makes it the standard choice for use with self-locking nuts, such as an AN365, MS21044, or a high-temperature all-metal locknut.
Why Choose AN6-52A?
The structural integrity of an aircraft is paramount. The quality of every fastener is a direct component of that integrity. Using a genuine AN6-52A bolt guarantees you are installing a component with a certified material strength, a protective plating designed for aviation environments, and precise dimensional tolerances. Substituting with uncertified commercial-grade hardware is extremely dangerous, as it can lead to joint failure from vibration, corrosion, or overloading. For any airworthy repair, trust only certified AN-standard hardware.
Order Your AN6-52A Bolts Now
Build and maintain your aircraft with the certified, high-strength hardware the industry trusts. Visit Airparts.aero to order your AN6-52A structural airframe bolts today.
The AN bolt part numbering system provides a complete and precise description of the fastener. In AN6-52A:
- AN: Signifies "Air Force/Navy," the original standardizing body.
- 6: Indicates the nominal shank diameter in sixteenths of an inch (6/16" or 3/8").
- 52: The first digit "5" represents the grip length in eighths of an inch (5/8"). However, for AN bolts longer than one inch, the first digit represents the whole inch number for the overall length, and the second digit represents the additional length in eighths. A "-52" bolt has an overall length of 5-2/8" or 5-1/4 inches (nominal). The precise overall length is 5-11/32".
- A: Denotes an undrilled shank, for use with a self-locking nut. If the "A" were absent (AN6-52), the shank would be drilled for a cotter pin to be used with a castellated nut.
A critical aspect of a proper installation is ensuring the grip length (the unthreaded portion) is equal to the thickness of the material being bolted, ensuring that the threads are not bearing any shear loads.
Note: This is a flight-critical structural component. Always verify the correct bolt part number (diameter and length) from the applicable aircraft maintenance manual or Illustrated Parts Catalog (IPC). Installation requires the use of a calibrated torque wrench and a corresponding certified nut.