Hand Tools Archive
They are marked. The one in your picture is the 49, the coarser of the two. I have at least two pairs. I used them extensively before I got Auriou rasps (my larger, coarser one is from Lie-Nielsen). I would not buy new Nicholsons, because they moved their manufacturing, but not their expertise, offshore. (In other words, they forgot how to properly make their patternmakers cabinet rasps). Also, Auriou makes left-handed rasps, which work much better for me.