What tool is used to prevent a Hi-Lok from rotating during installation?

The tool used to prevent a Hi-Lok from rotating during installation is the Allen wrench. A Hi-Lok is a type of fastener commonly used in the aerospace industry, characterized by a certain design that includes an internal hexagonal socket. When installing a Hi-Lok, it is essential to prevent it from rotating to ensure proper torque is applied and to align the fastener correctly with the components being joined.

An Allen wrench fits snugly into the internal hexagonal socket of the Hi-Lok, providing the necessary leverage to hold it in place while simultaneously allowing for the tightening or loosening of the fastener with another tool, typically a nutrunner or torque wrench. The design of the Allen wrench provides a secure grip that's essential for maintaining the stability of the Hi-Lok during installation.

In contrast, other tools like socket wrenches, screwdrivers, or pliers are not designed to properly engage with the Hi-Lok's internal geometry, which could lead to improper installation or damage to the fastener. Thus, the Allen wrench is uniquely suited for this specific application.