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The saw is an instrument of very ancient origin. We find it mentioned in the book of Isaiah at a period cotemporaneous with the building of Rome. It is represented on the obelisks of Egypt, and was in use among the Egyptians a thousand years before the days of Isaiah. The Greeks ascribe the invention of the saw to Deadalus, or his pupil Talus; but it is certainly of a more ancient date. Saw-mills were erected in Germany in the fourth century; in the island of Madeira in 1420; at Breslau, in Austria, in 1432; and in 1530 the first one in Norway was built. These were followed by many others all over Europe. The saw-mill, as a mechanism for cutting timber, had not been in use very long in some countries before the settlement of America. The early mode practiced by the American colonists of manufacturing boards and planks was either to saw them by hand, or to split them from the log, and then finish them by hewing with an ax. The first saw-mill erected in New England was in New Hampshire, near Portsmouth, some time previous to the year 1634. The first mill in Massachusetts was built about the year 1633. This was some years before the saw-mill was introduced into England. An early account of New York, published in 1708, speaks of Dutch-built mills for sawing timber, one of which would do more work in an hour than fifty men in two days. Saw-mills were erected on Manhattan Island as early as 1633. A saw-mill, down to the close of the last century, was quite a simple affair, and a mill that then cost £100 was considered better than the average. The modern saw-mill, driven by steam, differs very much from those built by the pilgrims of New England and the first planters at the South. An original engraving is given, in an old tract, entitled: “Virginia’s Discovery of Silk-Worms, with their benefit, and the implanting of mulberry-trees. Also the dressing and keeping of vines, for the rich trade of making wines there. Together with the making of the saw-mill, very useful in Virginia for cutting of timber and clapboards to build withall, and its conversion to other as profitable uses. By Ed. Williams. London. 1650.”
The above is fac-simile of the original cut found in the Patent Office Reports of 1850, pages 387 and 388. Contrast this with the fifty thousand lightning mills of the present day! The benefits conferred by steam in cutting timber, and in prompting invention in machinery applied to manufactures of wood, are among the most signal of its triumphs. The principle of construction of the saw is a series of knives set in a line. Every tooth is a knife and cuts a small portion of the material. Each is kept from cutting too deep by the tooth on either side. Each tooth should cut its allotted chip or slice of the material, carry it along, and drop it on the outside. The perfection of a saw is to cut as fast and smooth as possible with the least expenditure of power. To do this, it is evident that each and every tooth should be so constructed as to do its own proportionate amount of work. For if one tooth is out of shape or out of line with the others, it is not only useless, but hindrance and disadvantage to the others. Until quite recently, the teeth of all saws were made by cutting out portions of the plate so as to leave the necessary form for cutting. It probably never occurred to any one that other than solid teeth could be made. In 1852, Mr. James E. Emerson, employed as a superintendent of a saw-mill in California, while engaged in his work, realized practically how very great are the objections to the use of solid-toothed saws in districts remote from saw factories, and how great would be the advantages resulting from the adoption of properly constructed movable teeth. He demonstrated thoroughly that circular saws, with inserted teeth, will do more work with less expense of power than solid-toothed saws besides requiring no “gumming” and but little filing. Again, should teeth be broken, others could be substituted with scarcely no delay. He afterward returned to the Atlantic coast, and engaged in the manufacture of edge-tools, in Trenton, N.J. At a still later date he became the Superintendent of the American Saw Company’s Works. This company, whose office is at No. 2 Jacob Street, in this city, was organized for manufacturing circular saws with inserted teeth of his invention. At the late Exposition in Paris, this company exhibited a circular saw eighty-eight inches in diameter, which, it is believed, is the largest ever made. It was prepared at a cost of two thousand dollars, and, when finished, served for a table around which a numerous company partook of a sumptuous banquet served upon its surface.
Fig. 1 represents a section of a saw, showing how the teeth are inserted and held in the plate. “A” shows a tooth inserted in a section or piece of the saw-plate, “E”, “D” is the rivet, which is one half in the saw-plate and one half in the tooth. “B” - the incision in the saw-plate, showing the “V” made on the plate to fit the corresponding groove in the tooth “C”. This tooth is shown detached from the saw-plate, with the groove in the back or convex part. The tooth is inserted in the following manner: Place the groove in the back or convex part of the tooth, on the “V” that is fitted to receive it, driving the end which has one half of the rivet-hole in it into the saw-plate from the side. Next put in the rivet and head it up to fill the countersink. This having been done, cut or file it off smooth with the plate; the tooth will be held as firmly in the saw as a solid tooth. The teeth are made thicker at the point than the saw-plate, so that they can be easily spread to give them the required set. These teeth are all fitted with tools made expressly for the purpose. They do their work so accurately that new teeth, exactly fitting, can be furnished at any time. The latest important invention of Mr. Emerson consists in perforating solid-toothed saws with apertures, the object of which is to save frequent gumming, lessen the amount of filing and the liability of the saws heating on the rim. It also prevents the expansion and contraction of the rim of the saw, and the liability of its being broken from a fracture at the base of the teeth. This invariably begins at a sharp corner made by the file. In case a fracture commences in this kind of saw, it can only break through the bar between the aperture and the throat of the tooth. This aperture serves the same purpose as a round hole drilled at the end of a crack, which every practical person knows is the only means of preventing a further fracture in any kind of saw. The aperture also serves as a permanent guide in filing, and enables the operator to keep the teeth all of uniform shape and equal distances apart.
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