The grit survey reminded me of some things I hope to see some discussion on:
I think an important aspect of wheel grit on power grinders is often overlooked. IME, the edge you get is as much dependent on your "touch" and the "tuning" of your grinder as the specified grit of the wheel.
I would love to hear other opinions on this!
Disclaimer: These are just my thoughts and probably worth every cent you are paying for them!
If you use a light touch and have a fine-balanced smooth-running wheel, you are essentially riding the top surfaces of the grit, and an 60 grit wheel may be effectively performing like a 180 grit stone. The fast surface speed of the wheel makes it fairly easy to "ride the tops" and I can see the difference in the smoothness of the bevel depending on how much pressure I put on the wheel. I usually end any shaping/sharpening with a very light pass.
The system needs to be tuned, because, if the wheel is out-of-round, it tends to "dig into" the tool on the high spots. Similarly, vibration of the grinder causes the abrasive to impact the tool as you attempt to hold the tool steady.
I also wonder, but don't have much conjecture on the effects of dressing the wheel. Tormek maintains that their single stone produces an effective (IIRC) 200 or 1000 grit depending on how you dress it. Is their stone really that unique or are our dry stones (at least partially) prone to the same effect? Do I get a finer grit from my worn diamond dresser than my new one?