A112-12J - Textron Aviation OEM Hex Head Steel Shear Bolt

A112-12J – Textron Aviation OEM Hex Head Steel Shear Bolt

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Overview

The A112-12J is a flight-critical, genuine Textron Aviation Original Equipment Manufacturer (OEM) structural fastener, specifically engineered as a shear bolt. This is not a general-purpose machine bolt; it is a specialized component designed for use in primary structural joints where the predominant loads are in shear (perpendicular to the bolt's axis). Its design is characterized by a long, precision-ground grip (the unthreaded shank) and a shorter threaded portion, ensuring that shear forces are borne by the full diameter of the bolt.

Manufactured from high-strength alloy steel to a proprietary Textron drawing, this bolt is a cornerstone of the aircraft's structural integrity. It is typically used with a castellated shear nut and a cotter pin for positive locking. As the genuine OEM part, the A112-12J is the only fastener guaranteed to possess the exact material properties, shear strength, and dimensional tolerances required for its designated, high-stress application.

Key Features

• Genuine Textron Aviation OEM Part: Guarantees the part is fabricated to the exact Textron engineering drawing for material, heat treatment, and dimensional tolerances, ensuring structural integrity.

• Shear Application Design: Specifically engineered with an elongated, precision-ground grip and short threads to maximize its load-carrying capability in shear-critical joints.

• High-Strength Alloy Steel: Forged from a premium steel alloy and subjected to a rigorous heat treatment process to achieve the specific shear strength and ductility required for the application.

• Drilled Shank for Positive Locking: The shank is drilled to accommodate a cotter pin, providing a positive, mechanical lock when used with a castellated shear nut. This is the mandated locking method for most critical shear applications.

• Flight-Critical Structural Component: Used in primary load-bearing structures where joint integrity is essential for safety of flight.

Technical Specifications

• Part Number: A112-12J

• Component Type: Hex Head Shear Bolt

• OEM Authority: Textron Aviation

• Material: High-Strength Alloy Steel. The specific alloy and heat treatment must be confirmed by Textron Aviation documentation.

• Finish: Cadmium Plated or other protective coating per OEM drawing.

• Diameter: Per -12J specification. Must be confirmed by OEM documentation.

• Length: Per -12J specification. Must be confirmed by OEM documentation.

• Grip Length: Per -12J specification. Will constitute a majority of the bolt's overall length.

• Shank: Drilled for a cotter pin.

• Governing Specification: Textron Aviation Engineering Drawing A112.

Aircraft Compatibility

This is a proprietary OEM structural bolt used in specific, high-load applications on certain Textron Aviation aircraft.

• Applicable Platforms May Include:

  • Cessna Citation Series Business Jets

  • Beechcraft King Air, Premier, or Starship Series

  • Hawker Business Jets

Note: Verification of applicability is the absolute responsibility of the installer. The aircraft's current Structural Repair Manual (SRM) and Illustrated Parts Catalog (IPC) are the final and absolute authorities for confirming part number eligibility for a specific structural location.

Applications

• Primary structural joints loaded in shear, such as:

  • Wing attach fittings and spar connections.

  • Flight control surface hinges (aileron, elevator, rudder).

  • Landing gear trunnions and major component attachments.

Why Choose A112-12J?

The distinction between a shear bolt and a tension bolt is a fundamental principle of aircraft structural engineering. The A112-12J is engineered with the precise grip length and material shear strength required for its specific application. Substituting a standard AN tension bolt of the same diameter and length would be a catastrophic error; the shorter grip of the tension bolt would allow the weaker, notched threads to fall within the shear plane of the joint, drastically reducing its strength and leading to certain structural failure under design load. Only the genuine OEM part is certified for this flight-critical role.

The engineering principle of a shear bolt is to function as a high-strength pin that physically prevents the relative movement of two or more structural members. Unlike a tension joint, which relies on the high clamp load from a torqued bolt to create friction between the faying surfaces, a pure shear joint transmits its load directly through the bolt's shank. For this reason, the shear bolt's grip length is its most critical dimension. The design must ensure that the unthreaded, full-diameter shank extends completely through all members of the joint that are carrying the shear load. This places the "shear plane" squarely on the strongest part of the bolt. The shorter, threaded portion is only for the attachment of the nut and is designed to be completely outside of the load path. The material is also heat-treated to optimize its ultimate shear strength, which is the property that resists the "cutting" force, and to provide enough ductility to prevent a brittle fracture.

Note: This is a primary structural, flight-critical fastener. Installation and removal are structural maintenance tasks that must be performed by a certified A&P mechanic with structures experience, in strict accordance with the aircraft's Structural Repair Manual (SRM). It must be paired with a specific castellated shear nut (often a lower-profile AN320 nut) and a new cotter pin. The torque value applied is typically low, intended only to seat the fastener, as the load is not carried by clamp force.

Documentation

All technical data, including the precise material, dimensions, and installation procedures for the A112-12J bolt, are proprietary to Textron Aviation. This information is contained within the official Structural Repair Manual (SRM) and Illustrated Parts Catalog (IPC) for the applicable aircraft model. No public-facing documentation is available.