CHAPTER XXVIII.

WOODWORKING. EARLY MACHINES OF SIR SAMUEL BENTHAM--EVOLUTION OF THE SAW--CIRCULAR SAW--HAMMERING TO TENSION--STEAM FEED FOR SAW MILL CARRIAGE--QUARTER SAWING--THE BAND SAW--PLANING MACHINES--THE WOODWORTH PLANER--THE WOODBURY YIELDING PRESSURE BAR--THE UNIVERSAL WOODWORKER--THE BLANCHARD LATHE--MORTISING MACHINES--SPECIAL WOODWORKING MACHINES. Surrounded as we are in the modern home with beautiful and artistic furniture, and installed in comfortable and inexpensive houses, one does not appreciate the contrast which the life of the average citizen of to-day presents to that of his great-grandfather in the matter of his dwelling house appointments. A hundred years ago most of the dwellings of the middle and poorer classes were crudely made, with clap-boards and joists laboriously hewn with the broad ax, and the roof was covered with split shingles. Uncouth and clumsy doors, windows and blinds, were framed on the simplest utilitarian basis, and a scanty supply of rude hand-made furniture imperfectly filled the simple wants of the home. To-day nearly every cottage has beautifully moulded trimmings, paneled doors, handsomely carved mantels and turned balusters, all furnished at an insignificant price, and art has so added its æsthetic values to the furniture and other useful things in wood, that beautiful, artistic and tasteful homes are no longer confined to the rich, but may be enjoyed by all. This great change has been brought about by the sawmill, the planing machine, mortising and boring machines, and the turning lathe. Pre-eminent in the field of woodworking machinery, and worthy to be called the father of the art, is to be mentioned the name of Gen. Sir Samuel Bentham, of England, whose inventions in the last decade of the Eighteenth Century formed the nucleus of the modern art of woodworking. _The Saw_ was the great pioneer in woodworking machinery, and the circular saw has, in the Nineteenth Century, been the representative type. Pushing its way along the outskirts of civilization, its glistening and apparently motionless disk, filled with a hidden, but terrific energy, and singing a merry tune in the clearings, has transformed trees into tenements, forests into firesides, and altered the face of the earth, the record of its work being only measured by the immensity of the forests which it has depleted. It is not possible to fix the date of the first circular saw, for rotary cutting action dates from the ancient turning lathes. The earliest description of a circular saw is to be found in the British patent to Miller, No. 1,152, of 1777. It was not until the Nineteenth Century, however, that it was generally applied, and its great work belongs to this period. The preceding saws were of the straight, reciprocating kind. The old pit-saw is the earliest form, and in course of time the men were replaced by machinery to form the “muley” saw, the man in the pit being replaced by a mechanical “pitman,” which accounts for the etymology of the word. With the “muley” saw the log was held at each end, and each end shifted alternately to set for a new cut. The first development was along the lines of this form of saw, and to increase its efficiency the saws were arranged in gangs, so as to make a number of cuts at one pass of the log. This type was especially used in Europe, but on the up stroke there was no work being done, and hence half of the time was lost. This and other difficulties led finally to the adoption of the circular type, whose continuous cut and high speed saved much time and presented many other advantages. A representative example of the circular saw is given in Fig. 241. [Illustration: FIG. 241.--PORTABLE CIRCULAR SAW.] With the increased diameter and peripheral speed of the circular saw, however, a grave difficulty presented itself. The saw would heat at its periphery, and its rim portion expanding without commensurate expansion of the central portion, would cause the saw to crack and fly to pieces under the tremendous centrifugal force. This difficulty is provided for by what is known as “_hammering to tension_,” _i. e._, the saw is hammered to a gradually increasing state of compression from the rim to the center, thus causing an initial expansion or spread of the molecules of metal of the central parts of the saw, which is stored up as an elastic expansive force that accommodates itself to the tension caused by the expansion of the rim, and prevents the unequal and destructive strain, due to the expansion of the rim from the great heat of friction in passing through the log. Mounted upon a portable frame, this machine was put to its great work upon the logs in the forests of America, and for many years this type of sawmill held its sway, and an enormous amount of work was done through its agency. Among its useful accessories were the set-works for adjusting the log holding knees to the position for a new cut, log turners for rotating the log to change the plane of the cut, and the rack and pinion feed, by which the saw carriage was run back and forth. Following the rack and pinion feed came the rope feed, in which a rope wrapped around a drum was carried at its opposite ends over pulleys and back to the opposite ends of the carriage, which was thereby carried back and forth by the forward or backward movement of the drum. [Illustration: FIG. 242.--DIRECT-ACTING STEAM FEED SAWMILL CARRIAGE.] The greatest advance in sawmills in recent years, however, has been the steam feed, in which a very long steam cylinder was provided with a piston, whose long rod was directly attached to the saw carriage, and the latter moved back and forth by the admission of steam alternately to opposite sides of the piston. This type of feed, also known as the _shot gun_ feed, from the resemblance of the long cylinder to a gun barrel, was invented about twenty-five years ago, by De Witt C. Prescott, and is covered by his patent, No. 174,004, February 22, 1876, later improvements being shown in his patent, No. 360,972, April 12,