Which type of fastener is not intended to be removed after installation?

A set screw is specifically designed for permanent applications, where it remains in place and is not intended to be removed after installation. Set screws function primarily to secure objects in position without the use of a nut. Frequently, they are installed through a threaded hole and tightened against another object to hold it in place, such as in the case of securing a handle to a shaft. Once installed, set screws are typically meant to stay permanently, unless substantial pressure or force is applied to remove them, thus distinguishing them from fasteners like machine screws, wood screws, or self-tapping screws, which are commonly intended for easy removal and reinstallation.

The other options, such as machine screws and self-tapping screws, allow for disassembly, and wood screws can also be removed without significant difficulty. Therefore, set screws stand out as the fastener type designated for permanent installation, emphasizing their role in providing lasting security in a fixed position.