Rugged Recess Drive System for Flathead Threaded Fasteners

One hundred degree flathead recess machine screws used to secure aircraft panels suffer unacceptable failure rates during removal for maintenance and repair activities. We propose an innovative recess drive system, including the fastener recess and mating tool bit, which greatly increases removal torque capability and reduces the probability and severity of damage during fastener removal. Generous tool/recess clearance allows easy tool insertion and is tolerant of paint and dirt in the recess. The Phase I effort includes FEM stress analysis, geometric optimization, prototype fabrication and test, and documentation. The Phase I program objective is to demonstrate torque capability and damage resistance with prototype recess and tool hardware.