Jo-bolts, also known as internally threaded three-piece rivets, area type of blind fastener composed of a threaded steel alloy bolt, a threaded steel nut, and an expandable stainless steel sleeve. During installation, the bolt is turned while the nut is held, causing the sleeve to expand over the nut’s end, forming a blind head and clamping against the work. The Jo-bolt’s high shear and tensile strength make it ideal for applications with high stresses, such as late-model aircraft structures. These fasteners are permanent fixtures in areas rarely subjected to replacement or servicing, offering excellent resistance to vibration, weight savings, and quick installation by a single person.
Key Features of Jo-Bolts:
- Blind Installation: Jo-Bolts can be installed from one side of the structure, making them ideal for applications where the backside is inaccessible.
- High Strength: They offer excellent shear and tensile strength, which is crucial for maintaining the integrity of aircraft structures under load.
- Locking Mechanism: Jo-Bolts often have a locking feature to prevent the bolt from loosening under vibration, a common concern in aerospace applications.
- Material Compatibility: They are typically made from materials like steel, titanium, or aluminum, and are designed to be compatible with the materials they are fastening, helping to prevent galvanic corrosion.
- Flush Installation: Jo-Bolts can be installed so that they sit flush with the surface, reducing aerodynamic drag and providing a smooth finish.
How Jo-Bolts Work:
Jo-Bolts consist of a sleeve, a threaded bolt, and a locking collar. During installation, the bolt is inserted into the sleeve and then expanded as the nut is tightened, which creates a strong hold between the fastened materials. The bolt’s expansion locks the sleeve in place, providing a secure and reliable connection.
Because of their design and performance characteristics, Jo-Bolts are widely used in critical aerospace structures such as aircraft wings, fuselage panels, and other components that require robust, vibration-resistant fastening solutions.
Standard Removal Methods:
Because Jo-Bolts are often used as permanent fixtures in areas rarely subjected to replacement or servicing, they are not made with the maintenance technician and removal in mind. Technicians often struggle to remove these fasteners.
Traditionally, Jo-Bolts, like most other blind-bolt style fasteners, are removed using conventional methods like drilling or grinding. Due to the hardened stem running through the center of the shank, there’s a high risk of the drill veering off into the recesses of the cruciform. To prevent this, technicians often use a die or pencil grinder to shave down the stem before drilling. However, these methods are not only time-consuming and labor-intensive but also carry significant risks of damaging nearby structures. Additionally, they can produce debris or foreign object debris (FOD), which may compromise safety and reliability.
A Better Solution to Remove Jo-Bolts
E-Drill technology transforms the process of fastener removal, offering a quicker, more precise, and damage-free alternative to traditional techniques. By utilizing electro-discharge machining (EDM), E-Drill efficiently removes Jo-Bolt style fasteners with minimal impact on surrounding structures, significantly enhancing both time efficiency and safety in aerospace maintenance and repair.
Perfect Point provides specialized removal kits, such as the mechanical locator kit, tailored specifically for Jo-Bolt and other blind-bolt style fastener removal applications. This kit integrates seamlessly with existing vacuum locator tooling, securely locking into place through mechanical features like the cruciform recess in the Jo-Bolt head. This innovative approach eliminates the need for visual alignment, ensuring precise, mechanically concentric placement over the fastener head for a flawless cut every time.
Jo-Bolts are vital components in aerospace assembly and maintenance. While traditional removal methods often come with challenges and risks, E-Drill technology offers a superior alternative, boosting efficiency, accuracy, and safety in fastener removal operations. As the aerospace industry continues to advance, embracing cutting-edge technologies like E-Drill will be key to achieving the highest levels of performance and reliability.
Using E-Drill for Jo-Bolt removal presents several notable advantages. Its precision and efficiency significantly reduce the potential for damage to adjacent structures and minimize the generation of debris. Moreover, E-Drill’s non-contact technology provides a safer and more dependable solution for fastener removal in aerospace settings, maintaining structural integrity with minimal disruption.
