Which characteristic is crucial for materials used in manufacturing cutting tools?

The crucial characteristic for materials used in manufacturing cutting tools is high hardness. This property is essential because cutting tools must maintain their shape and sharpness while effectively cutting through other materials. High hardness allows cutting tools to withstand the intense mechanical stresses and wear that occur during the cutting process without deforming or losing their edge.

When a cutting tool is in use, it encounters significant friction and heat, so a material that can resist wear is necessary to prolong the tool's life and maintain performance. Typically, materials like high-speed steel, carbide, and ceramics, which exhibit high hardness, are chosen for their ability to withstand such conditions.

Ductility, thermal conductivity, and elasticity, while important in other contexts or applications, do not provide the critical capacity for resisting abrasive wear and preserving cutting efficiency that high hardness does for tools like drills and lathe bits. Therefore, prioritizing hardness in the selection of materials for cutting tools ensures functionality and durability in manufacturing processes.