Bad Axe is selling kits to make one or both of these, saws. The kerf saw is apparently used to establish a set of lines/kerfs to saw from. The frame saw is a size that Bad Axe thinks most people can use to make long difficult rips with. I am wondering if anyone has built these saws and has experience with them to report on. I believe Fidgen has written a book which describes making and using these tools.