Which factor directly relates to material properties in determining cutting speed?

• A. Strength and thermal conductivity of material
• B. Color of the material
• C. Manufacturer of tool
• D. Ambient temperature

Answer: (A)

The factor that directly relates to material properties in determining cutting speed is the material’s strength and thermal conductivity. Strength tells you how much cutting force the workpiece resists, which affects tool wear, deflection, and the safe speed at which you can cut without degrading the tool or part. Thermal conductivity shows how well heat is carried away from the cutting zone; materials that conduct heat well keep the cutting interface cooler, allowing higher speeds with less thermal damage and longer tool life. Together, these properties govern how the material behaves under cutting forces and heat, making them the primary drivers of feasible cutting speed.

Color has no bearing on machinability or heat/force response, the tool maker’s details don’t change the workpiece’s intrinsic properties, and ambient temperature is an external condition rather than a property of the material itself.