What is the common unit for cutting speed in turning and milling?

What is the common unit for cutting speed in turning and milling?

• A. Feet per minute
• B. Meters per minute (m/min)
• C. Meters per second
• D. Revolutions per minute

Answer: (B)

The key idea is that cutting speed is a linear velocity of the workpiece surface as it meets the cutting edge. In turning and milling, this tangential speed is expressed in linear units, typically meters per minute (m/min) in metric practice. It represents how far the surface travels past the tool in one minute, which is why the unit is linear rather than angular. Rotational speed (revolutions per minute) gives how fast the spindle turns, but it doesn’t directly specify how fast the edge is sliding along the workpiece surface. You’d convert RPM and the workpiece diameter into a linear speed, but RPM by itself isn’t the cutting speed. Feet per minute is used in some contexts, but in metric machining contexts, meters per minute is the standard. Meters per second is a valid velocity unit, but per-minute units are the conventional choice for cutting speed in machining data and practice.

The key idea is that cutting speed is a linear velocity of the workpiece surface as it meets the cutting edge. In turning and milling, this tangential speed is expressed in linear units, typically meters per minute (m/min) in metric practice. It represents how far the surface travels past the tool in one minute, which is why the unit is linear rather than angular.

Rotational speed (revolutions per minute) gives how fast the spindle turns, but it doesn’t directly specify how fast the edge is sliding along the workpiece surface. You’d convert RPM and the workpiece diameter into a linear speed, but RPM by itself isn’t the cutting speed. Feet per minute is used in some contexts, but in metric machining contexts, meters per minute is the standard. Meters per second is a valid velocity unit, but per-minute units are the conventional choice for cutting speed in machining data and practice.