For finishing rough casting surfaces, which file is typically selected?

• A. Mill file
• B. Round file
• C. Half-round file
• D. Plate file

Answer: (A)

Finishing rough casting surfaces requires a tool that can true a flat face with controlled material removal. A mill file is designed as a general flat file with a rectangular shape and straight cutting edges, giving uniform teeth along the length. This makes it ideal for smoothing and leveling large flat cast surfaces, removing burrs and high spots without digging into edges or creating hollows. The flat face lets you maintain a true, square surface as you work across the area, which is exactly what you need when bringing a rough casting to a final finish. Other file types serve different shapes: a round file handles holes and curved pockets; a half-round file suits both flat and curved regions but isn’t as efficient on a large flat surface; a plate file is wide and aggressive, useful for removing material quickly on very large flats but harder to control for a fine finish. So the mill file offers the best balance of control and efficiency for smoothing rough casting surfaces.