The subject of what is the best wheel grit for sharpening turning tools comes up fairly often, both here and other forums.
My input has always been the same. When I first started turning, we had a professional turner as a member of our club. He advised me to go with 80 grit. His reasoning was that 100 was too fine and would not sharpen well. And 60 was too coarse and removed too much steel and left a ragged edge. So, I bought an Israeli made blue 80 grit and have been using that for more than six years.
Today, I finally installed my new Delta slow grinder with my Wolverine rig. It has a white 60 grit and a white 120 grit. I wasn't real happy about this selection. But on testing, I got a big surprise. The 120 sharpens just fine. I'm real pleased with what it does and how it does it. I tested the 60 on an old Buck skew made with 'cast steel'. It also did a quite nice job and, IMHO, did not remove so much metal as to risk disaster.
The only puzzlement is that while sharpening with the 120, I could see white dust coming off.
A while back I sorta chided someone (Stu, wuz it you?) who mentioned that his sharpening wheels had gotten smaller. Seemed a near impossibility to me.
Of course, I know that sharpening/grinding wheels do have to get smaller with use. But, my grinder, that I use for real grinding, is about 40 years old and the wheels are not notably smaller than when new. In fact, I have measured and they are still 8". (mebbe a bit less)
But, these new white wheels do seem to be of a more friable material than the stuff the grinders are made from. So, I expect, I can look forward to shrinking wheels.
So, what is the best grit for sharpening turning tools?
Actually, is there a best?