I don't know what the super cobalt blank is make from but this might help.
Cobalt is in cutting tools to improve high temperture strenght for example, when using a end mill to cut steel the temperature at the cutting edge is very high so more cobalt in the steel is good to have. We never reach the high temperatures so cobalt doesn't help us
For a lathe tool we need elements in the steel that resist wear so once the edge is sharpened we want it to stay that way. Look for elements that form carbides like vanadium, tungten, chromium and moly. BUT Tool blanks are only a common HSS (which could be anything) and M2 which has to have a percent of basic elements to be called M2 so buy M2 when you can.
Grinding a blank with a 80 or 100 grit wheel is tough to do, it as to done with a 46 or maybe a 60 grit wheel. The wheel also has to be very agressive and still remain cool.
Hope this helps,
Doug