I make mine from worn out files by putting two together with a piece of PG 01 sanwiched at one end. I anneal the large end of the files, and either drill and tap for bolts, or just rivet them together. Then I grind the teeth from the working edges, squareing them at the same time on a flat table sander. Works well for me, and I make very good guard to blade fits, if I do say so. I also don't worry with using a safe edge file when using them. I seldom use the edge teeth on a file anyway, and have experienced no wear on the guides in twenty-five years of using them. I also use them for making a nice pair of matched ricasso borders, when I do high end work. I have a set of guides that cover most all the blade thicknesses I generally use. It does not take very long to make this type of guide, and they do work.