What type of broach is used to remove metal from the surface of a workpiece?

The correct choice is a slab broach, which is specifically designed for removing material from the surface of a workpiece. This type of broach is flat and has cutting teeth along its length, allowing it to effectively cut and shape the surface in a single pass. It is commonly used in applications where a precise, flat surface finish is required, such as in the machining of keyways or in creating flat surfaces on various components.

In contrast to the slab broach, other types like the round broach primarily focus on creating circular shapes or features, such as holes or internal surfaces, rather than where the goal is to remove surface material. A step broach is designed for stepped features and is not ideally suited for flat surfaces, while a surface broach, though similar in purpose, primarily operates in a different context or with different characteristics compared to the slab broach. Thus, the slab broach's unique design and intended use make it the best choice for surface material removal.