This little book is the natural successor to the "Simonds Guide for Filers and Sawyers" which has been in such demand that the supply is completely exhausted. In preparing a new edition it seemed wise to remodel the work and add much new material.

The Circular Saw is, therefore, taken by itself and treated in its relation both to the saw mill and woodworking shop. The convenient size and flexible cover are kept so that the book may be carried in the pocket. The headings are made prominent so that any subject may be turned to quickly for reference. At the same time the discussion proceeds in an orderly way so that a beginner may gain a clear idea of the development, manufacture, use, and care of the circular saw.

A companion work will follow immediately on "The Band Saw." A third volume will deal with "Machine Knives." Other books will appear until the line of Simonds Saw Steel Products is described in full.

Many of the illustrations in these books have been assembled on blueprint charts which can be tacked upon the wall of the filing room. Copies of these charts will be sent on request. The company has also outlined its welfare, educational, and efficiency work. Information on these subjects will be gladly furnished.

The Simonds Manufacturing Company was established in 1832; incorporated in 1868. During its long and successful history it has accumulated large resources of knowledge in the manufacture and use of saws and knives. Without presuming to be a final authority, the company is eager to aid the users of its tools to get the finest possible results in the woodworking field. Believing that Simonds Saw Steel Products are the best, the company would have all who employ them get the largest possible returns.

The great war is making large demands upon lumber men and woodworkers. The reconstruction period following the war will call for redoubled efforts. It is a patriotic duty to manufacture good tools and make them work to the utmost. The manufacturer, the filer, the sawyer, and the woodworker are in partnership to win the war and then to rebuild civilization.

Any corrections in the facts described in this book or suggestions as to its improvement will be welcomed. The company would appreciate a word from any who find it helpful.

 

Before history was written, primitive man was acquainted with the hand saw. Perhaps his knife became nicked and he found that by working it back and forth he could make it cut a new way. Or perhaps the suggestion came from the ragged edge of a shell, or the peculiar weapon of the saw fish.

But whence came the circular saw? This was a recent invention. The Pilgrims cut their boards by digging a pit, laying logs across, then working up and down a two handed saw. The man below was the pit sawyer, the man above, the top sawyer.

The first saw mill was built on the same principle only that the saw worked up and down by power. Then several saws were worked together in a gang. The next step was the use of the circular saw. Just when it was invented, or where, is uncertain. The first patent in England was granted in 1777. The practical use for wood-cutting began about 1790. The general use in the United States dates from about 1820. These early saws were thick and crude, made only on special order. The mandrel hole was square. The plate was not always solid, sometimes having a toothed rim and spokes like a wheel. For power, at first water was used, then steam. In some States they were driven by horse power. In 1839 the inserted tooth was invented, which proved a distinct advance over the solid tooth for some work.

CHAPTER III - Making a Circular Saw

Center Hole. The first operation in the making of a circular saw is the drilling of the center hole.

Toothing. Then comes the toothing, which is done with a die in a press (Fig. 2). Each fall of the die stamps out a gullet and forms a tooth. Circular saws have from 4 to 400 teeth. The gullets are rounded out with an emery wheel, and the teeth shaped more evenly.

Knocking Down. Then on the anvil the teeth are "knocked down" or straightened (Fig. 3).

Hardening. The saw is now fully formed ready to be hardened and tempered. These operations are most important and mysterious. The soft steel is heated in an oven until it becomes cherry red. It is then plunged suddenly into an oily hardening fluid. A wonderful internal change has taken place in the arrangement of the molecules, especially in the disposition of the carbon. The saw that could be bent and stamped so easily has now become very hard and brittle. It can be easily cracked and broken.

Tempering. Before it has time to cool it is heated again to about half the former temperature, this time under pressure. By this method much of the hardness is withdrawn and the saw comes to the right toughness and spring. The pressure keeps it very flat, otherwise the heat would greatly distort the plate. The inspector now tests the teeth by bending them back and forth (Fig. 4). If they show the right temper he passes the saw to the smith.

Smithing. Smithing is the most skilled operation in saw-making (Fig. 5). The smith lays the black saw on the anvil and examines it carefully with a straight edge. Any little lumps and hollows must be hammered out. The first steps in tensioning are taken. By tension is meant the stretching of the steel. The saw must be looser in the center than at the rim. This anticipates the cutting, when the rim will be stretched by the speed of revolution. The saw returns to the smith after each of the following operations, to be corrected, and to have the tension further improved.

Stamping. Figure 6 shows the master smith making his close examination before stamping the saw with its final marking.

Grinding. The saw can now be ground until its beautiful steel color is brought out and the plate is reduced to the right gauge or thickness (Fig. 7). The grindstones are of Ohio sandstone, some of the largest weighing eight tons.

Polishing. In the polishing operation the saw is made to revolve rapidly in a protected case (Fig. 8). Against the moving plate are held the polishing agents, first a block of emery, then cork with emery powder, finally  cotton waste and oil. The saw now has a beautiful mirror face.

Etching. The manufacturer is proud to put his name on it. Well-inked labels bearing the name "Simonds" are rubbed on the plate. The paper is washed away and strong acid brushed on. This eats its way into the parts left uncovered by the ink. When the ink is removed, the trade mark is so clear and deep that long usage will not wear it off.

Fitting. The saws which are to be set next have their teeth bent, one to the right, the other to the left (Fig. 9).

This is to give clearance. Other saws are roll swaged, i.e., the teeth are flattened or spread for clearance. The filing is done largely by machine and finished by hand (Fig. 10). The tooth that leans away from the filer receives the edge. Care is taken not to file the whole tooth, but only the part where the edge meets the wood.

Inspecting. The saw is finished. Before it is shipped the inspector makes a thorough examination of every part, comparing the specifications with the original order. Nothing escapes his careful attention.

Shipping. When he passes the saw it goes at once to the shipping room, where it is placed in a wooden case that covers the sharp teeth. The address of the customer is printed on with a stencil. The shipping bill is made out on the typewriter. The saw speeds on its way to the mill, where it will do its work. Circular saws have grown steadily in size until the largest practical saw is 90 inches. A show saw for the Alaska-Yukon Pacific Exposition in Seattle, 1909, was made 130 inches in diameter. Circular saws are divided into solid tooth and inserted tooth, splitting and cut-off, wood saws and metal saws, straight and concave.

While the band saw is coming more into favor the circular saw still holds its place, and will probably never be superseded for certain kinds of work.

Pre-eminent among these whirling discs of steel stand those branded "Simonds." In the quality of the steel, in the uniformity of temper, in the excellence of workmanship, they have never been surpassed.

Mill. A Circular Saw Mill is a machine in which a circular saw, driven by power, reduces logs into boards.

Power. The power used may be water, steam, gasoline or electric. While windmills or horses were occasionally tried in the early days, the first power to be generally employed was the waterfall. The types of water wheels have passed through many changes from the overshot to the turbine. Where mills are favorably located, water power is still utilized.

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