On the left, the previously-completed sock, after its trip through the washer to shrink it down. On the right, its mate in all its not-yet-shrunken glory.
For reference, here is the Coppergate sock from York:
I saw on Mistress Thora Sharptooth's nalbinding page that the rows of nalbinding on that sock are about 3.6 per centimeter. That's slightly less than 3mm per row. Eyeballing an inch as the length of my thumbtip, I'm getting 1.5 rows/cm in the toe (where the stitches are larger) and 1.9 rows/cm in the heel, where I tightened things up. Bigger stitches than the original, but also getting towards the limit of what I can do with my yarn. I don't know, but I would guess the original sock is done using a finer yarn.