"Proctologically Violated©®" wrote in message
...
Dust indeed!
So surprising how "apparently soft" green wheels are compared to grey Al
oxide "rock wheels", yet, the grey wheels just get the carbide hot, while
the green wheel really takes the carbide--and itself!--down.

You're confusing bond with abrasive hardness. Not the same thing. Silicon
carbide (the green wheels) is much harder than aluminum oxide, but it is
softly bonded so it breaks down rapidly to keep exposing new, sharp grain.
Because it's intended for grinding tungsten carbide, they know the grain
dulls quickly. They color code the wheels so you don't use them for other
purposes, knowing they break down rapidly and wouldn't perform well. The
typical silicon carbide wheel intended for other use is generally a shiny
black color.

Aluminum oxide wheels are bonded much harder, but the grain is too soft to
effectively grind tungsten carbide. The wheel glazes over and quits
cutting, but because it's bonded much harder, doesn't break down very fast
to expose new grains.

Harold