It's probably either 14 gauge (.083) or what we call split gauge (.078) I take a torch and slowly heat the edge half of the blade to a cherry red, ( just hot enough a magnet won't stick to it) Hold it there for a few seconds and quinch it in 130- 150 degree oil. A file shouldn't cut it. If it does, do it again cause you didn't get it hot enough. Make sure your oil is hot also, it won't work as well if it's cool. Once you have it tempered, stick it in your kitchen oven for 1 hour @ 400 degrees. It will be WAY, WAY better than untreated.