We are very apt to regard the saw not only as a very commonplace article, but as a fixed quantity which has always been the same and always will be. As a matter of fact, the saw has gone through a process of evolution the same as the electric motor, automobile, and aeroplane. New methods of its manufacture are constantly being invented and improvements made in its construction. Some of the steps in the process of making a hand saw are: rolling the steel plate of which the body is made, hardening, tempering, hammering or smithing, grinding, polishing, filing, setting, etching, handling, and blocking.
Fig. 104. Two methods of handling
The handling refers to the placing of the wooden handle and some idea of what it means is illustrated in [Fig. 104], showing two methods of attaching the apple wood handle.
Some idea of what the grinding means is shown by the tapers, or difference in the thickness of the steel, as shown at [Fig. 105], the thickness in one thousandths of an inch being given at the different points. It will be noticed that not only does the blade decrease in width from the handle out to the end of the saw, but the thickness decreases from the teeth to the top and also from the handle out to the end. This represents ideal saw construction, and it is found only in the good makes.
Fig. 105. Thickness of saw blade