There are times when I need to cut a curve in some wood, but either don’t want to use the band saw or it’s not available. In the past I’ve seen woodworkers using a bow saw to perform these types of cuts. Basically, this is a blade, placed in a frame with some mechanical means to tighten the blade. Many of the older saws used string or twine wrapped around the upper “horns” with a piece of wood in the middle used to both twist the line and to maintain the tension. Some of the newer designs use a metal shaft (almost like a super long bolt) with some type of nut on the end to initiate and maintain the tension on the blade.
I decided I was going to build my own a bow saw. I chose a design that was pleasing to my eyes (and would hold up with the tension required), found some good hard Maple for the uprights and some contrasting Padauk for the cross member. I drew out my design and cut the pieces to match. Historically, the cross member had tenons on each end, which matched up with a mortise in each upright. The fit of these joints is critical, since no glue is used. As the string/twine is tightened, it places great tension on the saw, and the joint changes its relationship slightly. If it was glued, then it wouldn’t have the give required and could cause issues. With the demanding fit of these joints, I decided to “cheat” to make sure everything fit just right and all stayed in the same plane. I used my Festool Domino to make mortises in each end of the cross member and also into the uprights. Then it was just a matter of inserting a Domino at each end of the cross member and slipping the three pieces together.
As for the string/twine, I purchased some braided fishing line (65 lbs. Test), which is easy to work with and adequately strong. I turned the handles for each end of the blade out of some Hard Maple, to a shape that was pleasing to my eye and hand. The only parts that I purchased, other than the fishing line, were the blades and blade holders. The blade holders were each epoxied into their respective handles and then I just slid the blade into the matching slots and I was ready to saw.
At present, I haven’t found any wide blades (for ripping) but I may cut a piece of band saw blade the correct length and insert an appropriately sized pin. These saws work well. One of the issues that many have is getting the blade set to the “proper” tension. I’d love to tell you to tension it until you are an octave above middle C, but I haven’t yet found any directly associable means to make this happen. When the blade is too loose, it will feel kind of spongy. When it is too tight, you’ll have a bunch of smaller pieces of wood ready for the fire. Seriously though, it is a fun build and yet another technique to learn.
Lee Laird has enjoyed woodworking for over 20 years. He is retired from the U.S.P.S. and works for Lie-Nielsen Toolworks as a show staff member, demonstrating tools and training customers.