Which type of mill is typically referred to as a plain mill?

A plain mill, often referred to as a slab mill or a wide mill cutter, is characterized by its broad, flat cutting surface that provides exceptional capabilities for machining flat surfaces and producing accurate, smooth finishes on workpieces. This type of milling cutter typically has edges that extend across the entire width, allowing it to remove material efficiently from the surface of the workpiece.

Plain mills are versatile and can be utilized in both horizontal and vertical milling machines. They are ideally suited for operations that require extensive cutting area and are commonly used in industrial settings for heavy stock removal. The design of this mill enables it to engage a larger area of the workpiece, leading to improved efficiency and productivity.

Other options do not accurately describe the nature of a plain mill. For instance, limiting the mill’s function to drilling, suggesting it operates solely with CNC technology, or defining it as a primarily manual mill fails to capture the essence of a plain mill's wide, flat cutting functionality that distinguishes it in metal cutting applications.