Thank you. Those are out of 15N20. I haven't had any trouble with the ones we use, but they are washed and dried right after use. These end up about .050" at the spine when finished.You have some great work here, Gene! I especially am interested in those paring knives up the page a ways. Are they carbon steel, or stainless? If they are carbon, do you have a problem with them rusting? How thick of steel do you use? Thanks!