Samarium Cobalt magnets

Samarium Cobalt magnets are hard and brittle
It is not possible to machine Samarium Cobalt magnets with conventional machining. Samarium Cobalt magnets can be abrasively machined with coolant served to absorb heating and dust. Without coolant, rare earth magnets could crack and chip by the heat produced during high speed cutting or grinding, and the sparks contain the easily oxidized grinding dust that could cause fire!
Samarium Cobalt magnets