Name three common cutting-tool materials.

• A. Aluminum, brass, bronze.
• B. Graphite, ceramic, diamond.
• C. High-speed steel (HSS), carbide, cobalt.
• D. Plastic, wood, rubber.

Answer: (C)

Cutting tools are made from materials that balance hardness, wear resistance, and the ability to hold an edge at high cutting temperatures. High-speed steel is valued for toughness and the ability to cut at higher speeds while still being relatively easy to sharpen and affordable. Carbide, a cemented blend of tungsten carbide with a cobalt binder, is much harder and can stay sharp at higher temperatures, enabling longer tool life and faster cutting—though it’s more brittle and requires proper tooling. Cobalt-containing alloys are used to improve hot hardness and wear resistance, especially in tools designed to operate under elevated heat, often in tough or high-speed cutting conditions. Together, these three cover a broad range of cutting needs: toughness and reuse with HSS, extreme edge retention with carbide, and high-temperature wear resistance with cobalt alloys.

Other options aren’t representative cutting-tool materials: softer metals like aluminum, brass, and bronze aren’t used for cutting tools; graphite isn’t a practical cutting-tool substrate; and while ceramics or diamond can be used in some cutting tools, the mix here isn’t the standard trio.