Frame Saws, Bow Saws, Turning Saws

Wooden frame saws, also called bow saws, are built with two arms, with a bar or beam mortised into the center of the arms, forming an "H" shape. The saw blade is attached across the bottom of the H, and a tensioning system across the top. The beam mortised into the centers of the two arms provides the fulcrum around which the blade is tensioned. Because the blade is in tension, it can be significantly thinner than an ordinary hand saw blade, which must be relatively beefy so as not to buckle. Traditionally the tension was provided with several loops of hemp string in a Spanish windlass, but today it is more common to use a rod tightened with a wing nut at one or both ends.

Frame saws can be used for almost any job: cross cutting, rip sawing, crosscutting wet wood, cutting curves, and cutting shapes within a board. By cross cutting we mean cutting across the grain of a board to shorten it. Rip sawing is cutting along the grain to straighten or narrow a board. Because the blade of a frame saw is easy to release, one can drill a pilot hole, undo one end of the blade, put it through the hole, and then re-attach the blade and cut out almost any kind of shape inside the board, a long through mortise, for instance. Every task demands its own kind of blade for optimal performance. Rip cutting needs a blade with relatively large, flat filed teeth. Crosscut blades have finer teeth filed at an angle. The turning saw uses a narrow blade with fine teeth set for a wider kerf to enable it to cut curves. A big advantage of frame saws is that the blades are relatively long and so permit faster cutting than other types.

Many people enjoy building their own frame saws. They are fairly easy to make, and can be very inexpensive without sacrificing any quality relative to a manufactured product. A nice bonus is that one can give free reign to fantasy in the design and ornamentation of the saw. With a blade, a few bits of hardware, and wood from the scrap pile, one can also knock together a serviceable frame for a special job in a few minutes. But be careful: we have seen, for example, a saw built with thin, elegant arms and an even thinner center beam. Lovely saw, but the builder soon found that the frame was no where near stiff enough to offset the blade tension needed, and the arms were too thin in section to provide a good grip. So one needs to pay attention to the strength and ergonomics parameters. For those interested in this end of woodworking we offer not only spare blades, but also steel blade holders, and twisted hemp cord. It might also be worth having a look at our short section on sharpening saw blades, or better, the directions from Friedrich Kollenrott, which are comprehensive, but unfortunately only in German. We find that the many of the ordinary frame saw blades offered today often have too much set in the teeth, and have not been very well sharpened. This does not need to be a problem if one knows how to fix this. Alternatively one can buy Japanese frame saw blades, which are optimally set and sharpened, but which cannot be re-sharpened.

These photos compare the different types of frame saw blades, rip, cross, wet wood, and turning saw blades more or less in their relative sizes.