The cable pulls blade taut and holds tension of arch of rim. The handle-sized piece of wood is approximately 16 inches long.
ILLUSTRATIONS: MOTHER EARTH NEWS STAFF
Any homesteader who has an old 26" bicycle rim, some scrap wood and the usual odds and ends kicking around his workshop will find he can make himself a brand new bow saw for the price of the blade alone (a 24" Swedish steel blade sells here on Long Island for $1.61).
The outside diameter of a 26" wheel rim is just shy of 24". This means that half of such a rim, plus a couple of handlesized pieces of wood, combined with a cable or rod tensioner, and two nails and two nuts (or two bolts and four nuts) are all you need to add to that $1.61 blade to make a bow saw that will cut as well as those selling for up to $10.00 or more. That's a pretty good bargain since every piece of hardware I've listed is free or potentially free.
When I made my first bicycle rim bow saw, I turned the blade to face out and cut off both wooden handles flush with the saw's face. It worked fine, but I found that holding the bow vertically up over the wood being cut tired my wrist.
I soon fixed that problem by replacing one handle with a longer piece of wood and turning the blade in. Now when I cut stove wood, the bow acts as a pendulum weight that naturally wants to keep the saw blade vertical for me, and I can still reverse the blade to cut out whenever I want to work on a log or limb that's too big or too unhandy to fit inside the saw's frame.