When using a saw, you'll notice that the kerf (the technical term for the groove the saw makes as it cuts) must be wider than the body of the blade or the blade will bind. To accomplish this some saws are tapered with the steel at the cutting edge thicker than the steel at the back. But the teeth on almost all saws are bent out a little so that they will cut wider then the thickness of the saw steel. The "set" of a saw blade refers to this the amount of clearance the saw teeth have over the width of the saw body. The more set a saw has - the more each tooth is bent out a little bit - the less chance of the saw binding the cut. But too much set and the saw will be hard to control. Most regular grade saws are shipped with too much set (which is good to remove), but after several sharpenings, you will find yourself needed to set the teeth. If the set isn't even, the saw won't cut straight: it will favor one side of the set or another. This principle applies to both Western and Japanese saws. A sharp saw is an amazing tool, so getting in the habit of setting the teeth can make a world of difference.
There are three basic ways of setting the teeth. The first, and coolest, way is by using a very tiny hammer against a small anvil to bang each tooth the appropriate amount in the right direction. First you do one side, then the other. This method goes fast, but unfortunately it requires an extreme amount of skill in order to hit ever other tooth squarely and with equal pressure. To be honest, I don't know anyone with the skill to set teeth this way. The second way is by using a "wrest." A wrest is a small piece of iron with slots cut into it. To use it, you do is hook each tooth into the slot and bend the tooth that way. This method is still used for very large timber saws, but it doesn't work very well with the tiny saw teeth we normally see in back and dovetail saws.
The final method, which is by far the most popular, is to use some sort of pistol grip saw set, just like these. The set hooks on to the saw, so that when you squeeze the handle, a plunger bends the teeth a specific amount. The amount is determined by the position of a movable anvil behind the plunger. Most saw sets available on the used market were designed to work on saws between 4 - 12 pt., which was by far the most popular range in the days of handsaws. This of course leaves you out of luck for the finer dovetail and tenon saws we all use now. These saw sets, however, are made in Japan, where very fine saws are common. The manufacturer is one of the last makers of saw sets and currently makes 2 models of saw sets: the gold-handled one for regular 4 - 12 pt. saws, and a finer blue one of 12 - 26 point saws. The blue saw set also has a much narrower plunger to take into account the smaller teeth.
If you sharpen only occasionally and want to get only one set, get the fine blue saw set. The gold saw set will do an easier job on larger handsaws. We offer a discount when you buy both pairs.