Jo-bolts are three-piece, internally threaded fasteners consisting of a threaded steel alloy bolt, a threaded steel nut, and an expandable stainless steel sleeve. These fasteners are preassembled at the factory and are designed for applications requiring high shear and tensile strength, particularly in the permanent structures of late-model aircraft. The installation process involves turning the bolt while holding the nut, causing the sleeve to expand and clamp the materials together, with a portion of the bolt breaking off upon completion. They offer advantages such as vibration resistance, weight savings, and the ability for single-person installation. Specialized pneumatic tools, such as the Avdel 07281, are used for high-speed installation in various industries.
Jo-Bolt Construction and Operation
The Jo-bolt system is comprised of three distinct components working in concert to create a strong, reliable fastening solution. The primary elements are a threaded steel alloy bolt, a threaded steel nut, and an expandable stainless steel sleeve. These components are initially assembled at the factory, streamlining the installation process.
The installation procedure relies on a rotational force applied to the bolt while the nut is held stationary. This action causes the stainless steel sleeve to expand outward, gripping both the nut and the surrounding material. As the sleeve expands, it forms a secure head and provides clamping force. A key characteristic of the Jo-bolt is that a portion of the bolt intentionally fractures during the installation process. This breakage is a designed feature, indicating that the sleeve has fully expanded and the fastener is properly secured.
The high shear and tensile strength characteristics of the Jo-bolt make it well-suited for applications where other blind fasteners may prove inadequate. They are frequently incorporated into the permanent structures of aircraft, specifically in areas not requiring frequent maintenance or replacement. However, caution should be exercised to prevent loose components from entering engine air intakes.
Applications and Advantages
Jo-bolts are particularly valuable in applications demanding high structural integrity and resistance to loosening. Their use in late-model aircraft highlights their suitability for environments subject to significant stress and vibration. Beyond aerospace, the fasteners are applicable across a wide range of industries due to their inherent benefits.
Several advantages contribute to the Jo-bolt’s appeal. Its excellent resistance to vibration ensures long-term reliability in dynamic environments. The fastener’s design contributes to weight savings, a critical factor in aerospace and other weight-sensitive applications. Furthermore, the installation process can be efficiently performed by a single person, reducing labor costs and streamlining assembly procedures.
However, the documentation notes a specific caution regarding their use. Because the Jo-bolt is a three-part fastener, it should not be used in locations where a detached component could be drawn into an engine air intake. This highlights the importance of careful consideration of the application environment during fastener selection.
Installation Tooling: The Avdel 07281
The Avdel 07281 is a pneumatic tool specifically designed for the high-speed installation of Avdel Jo-Bolt and Jo-Lock fasteners. It is intended for batch or flow-line assembly in diverse industrial settings. The tool’s design allows for efficient and consistent fastener placement, making it ideal for production environments.
Operating the Avdel 07281 requires adherence to specific safety guidelines. The operating pressure must not exceed 8 bar (120 lbf/in). The tool must never be operated without the full nose equipment in place. Furthermore, the use of safety glasses is mandatory for both the operator and anyone in the vicinity to protect against potential fastener projection.
The Avdel 07281 utilizes interchangeable nose assemblies tailored to specific fastener sizes and head types. Selecting the correct nose assembly is crucial for proper installation. If a complete tool is purchased, it will already be equipped with the appropriate nose assembly for the intended fastener. When replacing a nose assembly, it is essential to verify compatibility with the fastener being used, referencing the selection table provided in the tool’s documentation.
Nose Assembly Selection
Proper nose assembly selection is critical for the correct installation of Jo-Bolt fasteners using the Avdel 07281 tool. The documentation provides a table detailing nose assembly part numbers based on fastener head type and size. For a ¼ inch hexagon head, nose assembly part numbers 07280-07000 (Alloy Steel & .190) and 07281-00005 (Stainless Steel) are listed. Another option for the same head size is 07280-07100 (Alloy Steel) and 07281-00006 (Stainless Steel). The documentation emphasizes that knowing the original tool part number or the fastener details is essential for selecting the correct replacement nose assembly.
Safety Precautions
The operation of the Avdel 07281 pneumatic tool necessitates strict adherence to safety protocols. Beyond the general safety rules, specific precautions must be observed. Maintaining the operating pressure within the specified limit of 8 bar (120 lbf/in) is paramount. Operating the tool without the complete nose equipment is strictly prohibited.
The potential for fastener projection necessitates the mandatory use of safety glasses by both the operator and all individuals in the surrounding area. This precaution is essential to mitigate the risk of eye injury should a fastener become dislodged during the installation process. The documentation underscores the importance of prioritizing safety when working with pneumatic tools and high-speed fastening systems.
Tool Specifications and Maintenance
The Avdel 07281 tool specifications are outlined in the instruction manual, though the provided documentation does not detail the full range of specifications. The manual notes that Avdel maintains a policy of continuous development, and specifications are subject to change. Therefore, consulting the latest Avdel documentation is recommended for the most up-to-date information.
The documentation emphasizes the importance of using the correct nose assembly for the specific fastener being installed. Regular inspection and maintenance of the tool and its components are also crucial for ensuring optimal performance and safety.
Conclusion
Jo-bolts represent a robust fastening solution for applications demanding high strength and reliability, particularly in aerospace. Their three-piece construction, combined with specialized installation tooling like the Avdel 07281, enables efficient and secure fastening. Understanding the proper installation procedures, safety precautions, and nose assembly selection is crucial for maximizing the benefits of this fastening system. The provided documentation highlights the importance of adhering to manufacturer guidelines and prioritizing safety during all stages of installation and maintenance.