Which tool is specifically designed for holding metal firm while working?

The tool specifically designed for holding metal firmly while working is the machinist's vise. This tool features two parallel jaws that can be adjusted to securely grip workpieces, making it essential in machining, metalworking, and fabrication tasks. The structure of the machinist's vise allows it to accommodate various shapes and sizes of metal, providing stability and precision while the user drills, cuts, or performs other operations.

Its jaws are typically made from tough materials to withstand significant pressure and prevent deformation, ensuring that the workpiece remains stationary throughout the task. This is particularly important in tasks that require high levels of accuracy. The jaws can often be lined with a softer material, like rubber or plastic, to avoid scratching or damaging sensitive surfaces.

In contrast, while clamps are also used to hold objects, they are more versatile and not specifically tailored for metalworking. A bench press is meant for applying force to workpieces, and a hex key is a tool used for driving hexagonal sockets. Therefore, the machinist's vise stands out as the optimal tool designed explicitly for securely holding metal during various manual operations.