An interesting piece from Mountain Gazette--on working in the woods with hand tools.
To sharpen a saw you need an acute understanding of how and why it works. A crosscut saw works by cutting at a right angle to the wood grain (as in cutting across a tree trunk), using angled teeth that slice away at the wood fibers like carving knives. The most important attribute of a crosscut saw is that these sharp cutting teeth actually flare out wider than the saw blade itself. These cutters, as they are called, generally come in sets of two, sticking out about 1/100 of an inch to either side. This flaring, which is called the set, has two purposes. First, it causes the saw to actually bite in against the grain of the wood to create the cut, which is called the kerf. And it ensures that the kerf is wider than the saw, which keeps it from binding, or getting stuck in the wood.
