"Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote in message
. 3.70...
Jon Elson fired this volley in
:

The Cobalt
cutters last at least 3 X longer than HSS and only cost a few cents
more most of the time.


Of course, once you re-grind one, that advantage is mostly lost. The
gullets are still coated, but the primary and secondary reliefs are not.



Cobalt is not a coating; it's a premuim grade of tool steel that's been
formulated with a higher cobalt content, for the purpose of increasing
red-hardness and abrasion resistance.