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In woodworking and carpentry, hand saws, also known as "panel saws", "fish saws", are used to cut pieces of wood into different shapes. This is usually done in order to join the pieces together and carve a wooden object. They usually operate by having a series of sharp points of some substance that is harder than the wood being cut. The hand saw is a bit like a tenon saw, but with one flat, sharp edge. Handsaws have been around for thousands of years. Egyptian hieroglyphics exist depicting ancient woodworkers sawing boards into pieces. Ancient bow saws have been found in Japan. The cut patterns on ancient boards may be observed sometimes to bear the unique cutting marks left by saw blades, particularly if the wood was not 'smoothed up' by some method. As for preservation of handsaws, twenty-four saws from eighteenth-century England are known to survive.〔Olmert, Michael (1996). ''Milton's Teeth and Ovid's Umbrella: Curiouser & Curiouser Adventures in History'', p.178. Simon & Schuster, New York. ISBN 0-684-80164-7.〕 Materials for saw blades have varied over the ages. There were probably bronze saws in the time before steel making technology became extensively known and industrialized within the past thousand years or so. Sometimes cultures evolved two main types of saw teeth: the 'cross cut' saw teeth and the 'rip' saw teeth. These cut into the wood using different mechanisms. Wood is composed of many long cells running length-ways. Thus, crosscut saws have sawteeth that are usually shaped, often with a metal file, in such a way that they form a series of tiny knifelike edges.The wood cells are contacted by the knife-edge of the tooth and cut. Rip saws, on the other hand, are usually shaped so that they form a series of tiny chisel-like edges. The wood cells are contacted by the chisel and 'ripped' apart from the bundle of other cells. Of course either saw can be used either way, and . The development of saws was also affected by several factors. The first was the importance of wood to a society, the development of steel and other saw-making technologies and the type of power available. These factors were, in turn, influenced by the environment, such as the types of ores available, the types of trees nearby and the types of wood which was in those trees. Finally, the types of jobs the saws were to perform was also important in the development of the technology. Saws can also be considered 'pull cut' or 'push cut'. Ancient Egyptian saws have been said to be pull cut. Modern European saws (and those in European-derived cultures like that of the United States) generally have 'push cut' handsaws. Japanese handsaws are usually pull-cut and are still used today. In the 1930s, the Kulibert-Stanley Tool Company popularized an inexpensive saw. Many woodworkers have various theories about the advantages and disadvantages of pull vs. push, and even experts will disagree on these matters, including accuracy of cut, power available for cut, straightness of line, thinness of kerf (the slit in the wood that is made during cutting), etc. Among Basques and Australians, traditional hand sawing has generated rural sports. The Basque variant is called trontzalaritza. ==See also== *Types of saws *Musical saws *Saw set 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「hand saw」の詳細全文を読む スポンサード リンク
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