Building a hacksaw-bladed bow saw from <$10 in materials.
This is a classic design, a simple H-frame held together by some simple mortise and tenon joints and tensioned with some twisted string. This tension is important because these blades are narrow and would likely not stay straight enough to make a clean cut on their own. Other saws stay straight by being relatively thick and heavy (i.e. carpenter's saw), having a stiffener on the back (the back in back saw), or by cutting on the PULL rather than PUSH stroke (Japanese saws, like the one I used to cut the pieces for this project). Frame and bow saws trace their origins back through at least the Middle Ages, used in traditional woodworking even to the modern day.
So, I needed to cut some O1 tool steel (to make a new blade for my jack plane, but that's another Instructable) and my old, tiny hacksaw had had it. Could I buy a brand new hacksaw from the big box store? Absolutely. This is an exercise in making your own tools rather than buying them. I intend to use this as practice in general woodworking and for building a larger bow saw for unplugged woodworking. Everyone ought to have a hobby.
3/15 Edit: I am finally posting pictures of my (much!) larger bow saw, fitted with a somewhat more expensive, 600 mm crosscutting blade (~$20 on Amazon). All the skills you need to build this saw are already in this Instructable, read along to learn! More pictures at the end.
Note that 1"x2" dimensional lumber like the cheap stick you need for this project is actually about 0.75"x1.5", this is fine.
I have given two pictures as examples of the tool you will need. I used the first set, but could certainly have made do with something like the second. There is something beautiful about using hand tools to make more hand tools. If you didn't have a woodworking saw, you can make one!
You are responsible for your safety. Many of these tools have sharp edges and if you are uncomfortable handling any of them, please seek out assistance. They are not hard to learn. Protect your eyes, hands, feet, and brain.
* - You can definitely use different woods for this project, I had this scrap lying around and I was able to shape and work it extremely rapidly given its inherent softness. Hardwoods are definitely more traditional. I intend to use this very same process to make larger and finer saws in the future.