Stones for sharpening HSS cutting tools? edit, I have brazed carbide boring bars

Janderso said:
I have so many ways to grind HSS and carbide I rarely use the Baldor tool room grinder.
If I could find a source for quality diamond and green wheels maybe i'd use it.
The runout is so bad on the diamond wheel it's a royal PITA to use. I can dress the green wheel.
Baldor sells a diamond wheel for more than $1,000. That ain't gonna happen.
Shars is what I have now.
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I had some run out on my diamond wheel arbor and faced it up like a guy did on YouTube you posted. It was adapter, not the shaft or wheel. Did a little balancing on it and it’s been great ever since. I leave the tables at the relief angle after I did the main grinds to get the bits in the ball park. YMMV.
 
erikmannie said:
Does one need to wear a respirator when using a green wheel to sharpen carbide (e.g. brazed carbide boring bars)?
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I have seen some say that it's a good idea to wear a dust mask or respirator, but the cobalt in the grinding dust isn't in a really dangerous form. Chemically it's similar to chromium -- when it's in is +6 oxidation state it is very reactive and toxic but much less so when it is in its metallic state (zero oxidataion state).

The plating outfits use chromium salts so that's a completely different situation.

But if you want to be totally comfortable with the idea of having cobalt dust around, wear a mask while you're grinding carbide or HSS that contains cobalt.

The cobalt content in HSS alloys is fairly low typically 5 - 8%. It is used as a binder to hold the tungsten carbide particles together so the percentage could be higher in things like carbide inserts. It's high enough that inserts are attracted to a magnet.
 
I've got a tool & cutter grinder, Deckel knock off, Shars. Very easy to grind the boring bars on the diamond wheel. They are now selling what may be a better grinder. Those bars are pretty low quality. No idea what they are using for carbide. Probably recycled scrap that is crushed and sort of pressed back together. I had one of the tips pop off the first time I used it. Silver soldered it back on. The shanks on the set I've got are very soft and get dinged by the set screws. I finally added flats to the set screw area.
Don't breath carbide dust!
 
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