What term describes small imperfections left on a machined surface?

• A. Tool marks
• B. Burrs
• C. Cracks
• D. Scratches

Answer: (A)

Tool marks are the small ridges or patterns left on a machined surface created by the cutting tool as it engages and travels across the workpiece. These marks reflect the tool’s geometry, orientation, and the feed and depth of cut, making them a characteristic feature of the machining process and a key part of the surface finish. Burrs, by contrast, are raised projections at edges; cracks are fractures within the material; and scratches are surface gouges from external contact or finishing actions. Tool marks specifically arise from the cutting action itself, which is why this term best describes the imperfections on a machined surface.