Experiments You Can Do at Home - But Probably Shouldn't

Chapter 5
Heavy Metal » Building a Tough Bit

Building a Tough Bit

Making a tungsten carbide tool that can cut nearly anything. A visitor recently told me he remembered as a child watching his dad mixing dark powders and heating them in a graphite mold in the basement with an acetylene torch. He believes his father was making tungsten carbide tools from scratch. I'd never heard of anyone doing that, and the story sent me on a weeks-long quest to find out if it was even possible.

Tungsten carbide is used to make high-end saw blades and drill bits. It's harder than just about anything short of diamond. A matrix of cobalt metal holds together small particles of the super-hard tungsten carbide, similar to the way glue holds the grit on sandpaper. But those bits are made in factories using inert-atmosphere furnaces and massive, hot isostatic presses that fuse the powdered ingredients. You couldn't seriously do it in your own basement. Could you?

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