I use a bench grinder to grind my tungsten's, but the stone is a bit rough. I chuck them in a drill then put a finer finish on them with a 120 roloc disc. What grade stone would be most suitable ?
For 99% of jobs i just use the finer of the two wheels supplied on a cheap bench grinder, typically they're 60 grit (with 36 on the coarse side). For low amperage work i tickle 'em again using whatever is to hand and is finer like a 150 grit flap wheel. One of these days (when there's nothing more important/interesting to spend money on) i might fit a 300 grit CBN or diamond type 1A1 (peripheral) wheel to a bench grinder and stick a 600 grit lapidary disc to the side of it
I just use the finer wheel on my bench grinder. It not great to put the tungsten in the drill, if that's what you mean because the grind marks will be around the point causing the arc to wander at low amps, It's better to have radial grind marks.