In Makeshift Workshop Skills for Survival and Self-Reliance (Paladin Press, 2009), author James Ballou provides creative and, certainly, unconventional workshop skills from construction to repair. Ballou also offers useful DIY projects for around the shop. The following excerpt from chapter four, “Improvised Tools," gives a step-by-step guide, based on real-life trial and error, on how to successfully turn scrap metal into a homemade saw blade.
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Homemade Saw Blades
If you already have plenty of good files and saw blades of every variety, making numerous other kinds of hand tools is not usually a problem. But have you ever tried to create an effective homemade saw blade from scrap? This objective nagged me as an irresistible challenge until I built some experimental saws and tested them. Read on, and I will share the results of my research and experimentation with makeshift saws.
To start, it’s important to understand exactly how saw teeth cut. Whereas a knife blade uses the very gradual wedge shape of its tapered edge to separate material in the cutting or slicing process, saw teeth actually act like a series of tiny chisels in a row, each chiseling off small bits of material during the sawing. In other words, a knife blade essentially wedges material apart at a microscopic level, while a saw chews or chisels out material. Hence, you wouldn’t want your saw teeth to taper along the sides like the edge of a knife blade.
If you look closely at a lot of common saw blades, you can see that in many cases the teeth are offset from center in both directions in an alternating sequence. This is to ensure that they will chisel out a larger slot in the material being sawn than the thickness of the blade, giving the blade adequate clearance to move back and forth in the deepening cut without binding. It also sets those tiny chisels in position to bite off more material during every pass.
Improvised saw blades might be fabricated in a number of ways, depending upon the tools and materials available to work with and the specific sawing tasks at hand. I created some functional homemade saws for rough-cutting wood using mild steel for the blades. The soft, mild steel was easy for me to work but obviously was not the best material for saw teeth, as it probably won’t stay sharp very long during prolonged use. Even so, my makeshift saws proved to be surprisingly effective during my sawing experiments.
The catch to my method was that I needed one saw to make another, because my makeshift teeth were created with a hacksaw. Without access to a hacksaw, functional homemade saw blade teeth could still be created with a sharp chisel and a forge, by hot cutting the metal over a cutting block or anvil. We should keep in mind that the first saw blade made of metal had to have been made entirely without sawing out the teeth.
A thin saw blade should be made of spring steel, or at least properly tempered steel, to allow some degree of flex and avoid crumpling or breaking under stress. Steel that is too hard to cut or file easily can be softened by annealing and, after the work is completed, rehardened.
My first homemade saw blade was not a very good design. The thickness of the teeth was the same as the body of the blade, and the blade was thicker and taller than it needed to be for the smoothest sawing action. Nor were the shape of the teeth ideal.
I made a close inspection of the teeth of a large crosscut saw to get an idea about how I should shape the teeth on my second homemade saw blade. Based on my observations, I cut the teeth with alternating angles for superior chiseling action, and I made the body of the blade narrower, allowing it to pass through the cut with less bind or friction. Still plenty of room for improvement, but this second homemade saw chewed through a couple of thick tree branches without any trouble.
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This material was excerpted from Makeshift Workshop Skills for Survival and Self-Reliance by James Ballou with the permission of the publisher, Paladin Press. The material is copyrighted and cannot be reused or reprinted without written permission. Buy this book from our store: Makeshift Workshop Skills.