An Industry That Requires Intelligent Labor and Many Delicate Processes.
How the Large Steel Plates Are Taken And Made to Suit the Uses of Man—Saws of All Sizes and Descriptions.
The complexity of the industries to-day found in this city will, in a very few years, cause it to rank with the greatest manufacturing centers of this country. They are as varied as opportunity and science can suggest or capital establish. In any one of them there is a lesson that few, except those engaged in the work, know anything about, but it cannot be without interest even to those whose fancies or likings tend very little to mechanicism.
Each manufactory has scores of object lessons and none present more interesting details than saw-making. At an establishment of this kind a Journal reporter yesterday witnessed the evolution of a saw from the plate of steel to the packing house. Here, many years ago, the owner of the factory visited, made the first saw himself, without capital or assistants, and with nothing but industry to promise the large establishment that is the outgrowth of his little shop.
It is in the steel-room, where the plate stock coming from the furnaces of both this country and England is stored, that the lesson of the reporter began. The plates are of a dunn steel-gray, and are about the size and the exact shape of the saws which are to be made from them, either circular oblong for cross-cut or circular saws.
The plates are from this room taken to the cutting department, where long rows of powerful punches, with dies precisely the shape of the teeth to be cut, push them out with the same readiness that a knife cuts a piece of cheese, and almost as noiselessly. The machines for the cross-cut saws have but one punch, while those for circular saws have four, arranged at the ends of a cross, in sectional shape, adjusted to all work in unison and with an accuracy minute to a hair.
The operation of the punches is very rapid considering the fact that at every stroke they penetrate a thick sheet of steel. The teeth of a six-foot cross-cut saw were cut in just one minute. Almost endless varieties of teeth are made, adapted to widely different uses. The saw passes from the cutters to the devilers, by whom it is slightly prepared, outlined, so to speak, for filing.
The saw is then taken to the tempering-room, heated to a white heat in special ovens in which in used natural gas, by a secret process. The steel is then drawn from the oven by large clamps and plunged into a bath of cold oil, where the saw is allowed to cool to blackness, or rather a deep bluish-black hue. The darker this hue the higher the temper of the saw.
It is then submitted to a great lateral compression in a special machine, after which it is carried to the smithing department. Here is where the most expert work of all is done, and the men are paid very high wages. They are known distinctively as “saw-makers,” though, of course, all of the hands have a right to that name.
The saw is laid by the smith on an anvil having a surface closely resembling a fine plate-glass mirror, in which every object is clearly reflected. This is absolutely true in level, and upon it the smith corrects, by judicious tapping with an odd shaped hammer resembling a right-angle of iron, the distortions of the saw-plate resulting from unequal shrinkage in the oil bath.
From the smithing department the saw passes to the grinding-room, where huge grindstones, six feet in diameter and weighing several tons, have 300 revolutions per minute in opposite directions. They are set vertically, edge to edge, one above the other. Powerful steel clamping rollers catch the saw-blade and pass it automatically back and forth between these grinders, which remove the blackness of the steel. Finally the main surface is white, but full of shallow depressions of the original black hue.
Continued grinding levels these out too, until, five minutes from the time it made its first pass between the massive grindstones, the saw comes out smoothed to mathematical accuracy of surface. The saw now goes through a series of rapid handlings and corrections. It returns first to the smiths, who commence the high polish of its surface by gentle taps of the hammer, delivered in quick succession.
After this it passes to the filing and swedging department, where the teeth are ground by emery wheels to sharpness, and their tips swedged, or spread by smart strokes from a die of the desired shape, wielded by the workman’s own hand. Machine swedges are being introduced, but the work is still largely done by hand.
The saw now reaches the polishing department, where it is passed between very fine grinders, somewhat similar to those described above, but with the addition of fine emery powder and water. From this machine it comes in about two minutes, having the beautiful silver-colored surface.
The last touch of the manufacturer is now to be applied to the saw, and the process is, perhaps, the finest of all. It is taken to the etching department. The name has an artistic sound and very appropriately, for it is, indeed, artistic work.
The shining saw plate is laid upon a broad table and the etcher takes from a pigeon-hole in a large case, filled with them, the printing-plate he desires. It is a small steel engraving instrument, having the firm’s name and various intaglio devices delicately traced on its surface, which is about six inches long and four inches wide.
The surface incision of this engraver is first filled with greasy jet-black ink, the consistency of putty. A piece of tissue paper is then laid upon it and placed in a small press, resembling a common letter-press, and the ink comes out of the engraving on the plate and leaves the pattern on the paper. The paper is then placed, ink-side down, upon the steel saw-plate, moistened with water and instantly removed. This leaves all the fine black tracery on the plate itself.
This surface is varnished over with a secret chemical combination. After it is dry another secret compound is then washed over it. It disolves the ink and leaves the varnish. The plate is now ready for the etcher’s acids. He takes a true artist’s swab and brushes the acid quickly over the surface. Instantly there appears on the before colorless steel, a deeply etched jet black tracing of the original design and the saw is packed and sent out into the market bearing this handsome design.
The making of band saws is in every sense similar to the manufacture of other saws, except that their great length (some times sixty-five feet) requires much more care, and the soldering together of the band is a very particular and carefully managed process. The first band saw was made in this factory five years ago, and recently a large separate three-story house had to be erected for this department so great has been the growth of the industry.
As the reporter was leaving the works he entered a shed in the outer yard where more weight per square foot rests on the earth than at any other spot in Indianapolis, except at the Capitol. It was the storage shed where the supply of grindstones is kept, and 150 of these monsters, weighing 3,000 pounds each, were piled together in a small space, giving a total pressure of half a million avoirdupois.
The making of saws enlists a very intelligent high class of labor. The workmen are well paid. Several of the men employed at the factory where these observations were made have invented valuable machinery.
The Indianapolis Journal – February 17, 1889