Define cutting speed in machining.

• A. The rotational speed of the tool, typically in surface feet per minute (SFM) or meters per minute.
• B. The distance the tool advances per revolution.
• C. The depth of cut per pass.
• D. The width of cut.

Answer: (A)

Cutting speed is the linear speed of the cutting edge relative to the workpiece, usually given as surface speed in SFM (feet per minute) or m/min. It depends on how fast the tool spins and how large the tool is at the cutting edge: as rpm or tool diameter increases, the edge moves faster across the material. A useful way to think about it is that the edge speed roughly scales with the product of the tool diameter and rpm (V ≈ π × D × N). This speed is a key factor in heat generation and tool life, so it’s chosen to balance productivity with tool wear. The other terms refer to different parameters: how far the tool advances per revolution (feed per revolution), how deep the tool cuts per pass (depth of cut), and how wide the cut is (width of cut or engaged width), which do not define cutting speed.