This type of pattern on metal is made by a process called?

The correct answer is knurling. Knurling is a manufacturing process that creates a textured pattern on the surface of metal, typically in the form of a crisscross or diamond pattern. This process is often used to enhance grip on handles or for decorative purposes. By rolling a tool with a specific shape over the metal surface, it deforms the material, producing a raised pattern.

Knurling is particularly valuable in applications where a better tactile surface is needed for gripping, such as on tool handles or knobs. This increased grip can improve safety and functionality, making it a common choice in various mechanical and ergonomic designs.