This first image is of the blade after being sharpened with my very well loved 600# diamond stones that have seen well over 1000 uses:



And here is the blade after being sharpened with some relatively new 600# diamond stones which have sharpened less than a dozen knives:



The difference is pretty dramatic. With my old 600# stones I get a very polished looking edge that easily zips through paper, shaves arm hair and does every day work very nicely. With the new stones, the edge is very toothy and snags in paper, doesn't shave well but is ferocious on squishy tomatoes when slice cutting.

is the difference due to difference in material of the stone, or simply the lack of 'break in' ?

ShmuelMandelbaum wrote:


That's a great question which I assumed was obvious and now see exactly why it's not - thank you for asking it! The stones have the exact same make up, the only difference is how well broken in my older set is. I just did another little experiment with both stones - I decided to see how each edge would look after 20 strokes with the 1 Micron Diamond and Leather Strops. Here are the pictures:


20 Strokes with 1um Diamond and Leather Strops over the new 600# stones


20 Strokes with 1um Diamond and Leather Strops over the old 600# stones