Which of the following tools is specifically designed to mill flat surfaces?

The tool specifically designed to mill flat surfaces is the slab mill. Slab mills are large, flat milling tools that are used primarily for machining flat surfaces, which allows for efficient removal of material from large workpieces. They generally have numerous cutting teeth located on the periphery of the tool, providing a wide cutting surface that can cover substantial areas in one pass.

Unlike other tools, slab mills are particularly advantageous for horizontal milling machines and can produce a flat surface with great precision. Their design and function make them suitable for applications that require substantial material removal.

In comparison, end mills and face mills are also utilized to create flat surfaces, but they have different primary functions. End mills are versatile tools mainly designed for plunging, slotting, and contouring and can be used for flat surfaces but are not specialized for this purpose. Face mills, while effective at producing flat surfaces, usually have an orientation angle and are more commonly used for finishing surfaces or creating a flat surface at the face rather than deep material removal like slab mills. Shoulder mills, on the other hand, are designed to create features such as shoulders and grooves rather than strictly flat surfaces.