Aerospace Fastener Installation Tool

Contamination and ergonomics are critical concerns in aerospace manufacturing, especially with fastener designs that include torque-rated breakaway pintails. Howmet Aerospace challenged us to develop a lightweight, ergonomic installation tool capable of handling a variety of Ergo-Tech® fasteners while improving pintail collection. Our design balances usability, efficiency, and reliability to enhance aerospace manufacturing methods. 

Design A incorporates a framed motor, offering a more robust structure. Instead of dropping pintails forward, this design routes them through the shaft and ejects them from the back of the tool. This method is similar to previous Howmet tools but increases pintail storage capacity and improves ergonomics by redistributing weight. 

A key challenge with this design was ensuring pintails did not get stuck at the collection exit. To mitigate this, we are exploring a vacuum-assisted system that creates suction, ensuring pintails flow smoothly into the collection box without clogging. 

Design B utilizes a frameless motor, making it more compact and reducing overall tool weight. The pintail collection system is positioned forward of the motor and gearbox, allowing pintails to drop out of the tool into a side pouch or mounted container. This design ensures that pintails are managed efficiently without adding bulk to the tool. 

By keeping the tool lightweight and directing pintails forward, this design improves handling and reduces operator fatigue. The streamlined form factor allows technicians to work in tight spaces without compromising usability. 

After careful evaluation, the sponsor selected a motor that balanced high torque with a compact form factor. This decision enabled finalizing the shell design for 3D modeling and printing. The shell was ergonomically designed, with thorough testing of trigger placement, grip angle, and size to ensure user comfort. A quick-change nozzle assembly at the front allows for easy swapping between three different fastener types without disassembly, using a spring-loaded ball mechanism similar to an impact driver for secure, rapid changes.

The core drive system consists of custom-machined metal parts supplied by Howmet based on our technical drawings. These metal components create a rigid structure that handles all torque loads, relieving the 3D-printed shell from mechanical stress. The metal assembly fits snugly inside the clamshell-style shell, providing strength and durability essential for reliable operation.

The prototype features a side bag clipped to the user’s belt that houses the battery, a removable pintail container, the vacuum pump, and an off-the-shelf alpha controller. The vacuum pump pressurizes the pintail container, creating suction that pulls broken fastener pieces (pintails) through the system like a shop vacuum. The container design prevents debris from entering the vacuum pump, ensuring smooth and effective debris collection.

We successfully built two functional prototypes that were showcased at the Cal Poly Expo. The client expressed strong satisfaction with the results, noting that the design meets all main objectives. This project solves an important problem and has the potential to form the foundation of a new product line for future production.