I'm in the process of making a blade for my bow saw, and have the frame roughed out.
I've made much fancier bow saws in the past, but never a turning saw. For this saw, I'm going quite simple and functional, and utilizing hardware (bolts for the pins, and threaded rod and wingnuts for the tension). My goal is a general, all purpose saw for joinery, ripping, and maybe some extra blades for crosscuts and turning/curves.
It uses a simple H joint which allows me to easily make different stretchers for different blade lengths, and I can adjust the depth of the cut for particularly wide boards, or if I want more tension.
I also have a string and toggle for it which I often prefer using, which isn't pictured here. The blade is incomplete, and I will likely be replacing it at some point as the steel I am using is a bit too thin; though, it seems that I can tension it enough to make it work.
I'm using Paul Seller's method of recutting the teeth using a hacksaw in conjunction with the saw file. The teeth are 9TPI. I started off trying to do 16TPI, but that was a bit too small for my skill level and I couldn't get them evenly spaced. I'd definitely recommend going a bit larger for your first blade.
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A picture of the frame.
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You can see that, despite the blade being very thin, I can get a decent level of tension such that it doesn't seem flex too much. Here, I'm holding the saw blade horizontal, and the saw hangs at about a 45 degree angle under its own weight; it's fairly heavy, as it's made of oak and uses a steel threaded rod for tension.
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I've got some .025" steel coming in that should work better than the very thin .018" stuff that I'm using now. I will say that the thinness of the blade does seem like it will allow for an effortless cut; even with completely dull, barely shaped teeth, it cuts fairly easily already! But this extremely thin steel is hellish on my tools. I've already completely destroyed a hacksaw blade from vibrations and snagging that you get with stock that is too thin. I also destroyed a nicholson saw file, but I think the file itself was bad because I have an older one that is continuing to cut just fine. If anyone has recommendations for good, quality saw files, do tell!