This entry deserves much attention, more than I can afford right now. Below is an illustration designed to provide a "quick-and-dirty" answer for a question in the Qustion Box.
Fig. 9 shows a hand saw with the shapes and names of the various parts indicated. It can be toothed as a cross cut or as a rip saw. Its blade is taper ground, that is, the thickness is not the same in all parts of the blade. The butt and the blade along the entire length of the tooth edge are of equal thickness, but from the teeth to the back and from the butt to the toe, the gauge or thickness decreases gradually. Hand saws are used for cutting wood to size and for general purposes. A back saw, Fig. 10, is finer toothed and the blade is made of thinner metal of uniform thickness, consequently it is admirably suited to fine work. The metal back reinforces the blade and keeps it from buckling or bending when in use. Coping, turning and compass saws are used for sawing curves.
In using the hand saw the wood should be held firmly over a saw horse with the knee against or on the wood. Fig. 11 shows the starting position with the left hand holding the board and at the same time guiding the saw. The first movement should be a short, slow, dragging stroke and the next a slow thrust, both without much pressure or weight applied to the saw. Once the saw kerf is started the saw is guided by the twist and slant given to the handle with the right hand. In sawing. it is always held at about the angle illustrated.
The teeth of a cross cut saw act on a board something like a series of knives operated in pairs. The teeth are shaped as at A-Fig. 3. [In a process called "set", the teeth of a saw are designed to cut a kerf wider than the blade's thickness.] One tooth is beveled on one side, the next tooth on the opposite side. This makes an extreme point on each tooth, but one is on one side of the saw blade and the next is on the opposite side. A saw with teeth shaped like this, when drawn over a board, does in one operation exactly what a knife might be made to do in several, i. e., scores the wood in two places and chips out the particles between, C-D and E-Fig. 2. A saw constructed in this way would not, however, penetrate far into the wood until the blade would begin to bind. To overcome this the points of the teeth are bent outward, first one to one side, then the next to the opposite side. A saw with the teeth so bent is said to possess "set." Fig. 3 shows several views of a cross cut saw, with and without set, also its action on wood. The cut or crack made in the wood by the saw is called the kerf. A cross cut saw can also be made to cut in the direction of the grain but when used for this purpose its action is slow and unsatisfactory.
The teeth of a rip saw are somewhat like chisels. They are not sharpened to a bevel on the edge and they are not pointed. As has been stated, the fibers in wood separate easily in the direction of the grain and are easily removed once they are cut. Cutting with the grain requires no scoring. A chisel pushed into the wood as at A-Fig. 5, only cuts across a group of fibers but the piece in front of it is easily forced out. If another chisel were pushed into the wood a short distance behind the first and in line with it, the result would be another piece of wood forced out. The rip saw works on this principle, each tooth being similar to a chisel. Like the cross cut saw, it would bind unless "set" to give clearance. Fig. 4, shows several views of a rip saw with and without set. Fig. 6 shows its action on wood.
Source: Harry E. Wood and James H Smith, Prevocational and Industrial Arts Chicago: Atkinson, Mentzer, and Company, 1919, pages 6-7.
The Civil War period marked a turning point in tool design, as it did for so much Americana. Before that time, the word tool meant an implement that could make one thing at a time; mass-production tools then entered the scene, and the word tool, which had meant only "hand tool," took on many added meanings. Finally the word tool came to mean any item having to do with the production of an item; it could be the machine and also the building that housed the machine. Even the salesmen, the advertising gadgets, and the business offices are "tools of the trade."
Generally speaking, hand tools made after the Civil War period lacked the simple beauty of those of the ante-bellum period. Things were made to sell quickly, things were made in large quantities so that they could be catalogued identically, and hand-made implements began to disappear. Wooden handles became "fancier," more curved and ornamental, but the severe beauty of folk art and primitive usage was lost. Saw handles became "trickier"; they were designed to appeal to the eye instead of to fit the hand. Axe handles, which had always been almost straight, as a good club should be, took on curves such as the "fawn foot" and the "scroll knob." By 1885, handles on axes and adzes had become almost too curved, but by the 1900s they settled down to a sensible and standard design, such as that of those you can buy now at the hardware store.
Source:Eric Sloane, A Museum of Early American Tools New York: Ballantine Books, 1964, page 5.