RE: Sharpening Carbon steel
A bastard file is a single cut, but it's a finer cut than a plain single.Kinda like the difference between coarse sandpaper and fine. Size also makes a difference. A big file is coarser than a small one. So, when theyrecommend a 10" file, then they must have found out that particular size and cut works best for the edge they recommend. Nicholson makes a good file and I've seen 'em even at wally world.