Files Once Made From Fish Skins

Probably there is no tool so universally used and so carelessless handled as the file. Perhaps because it is so inexpensive, a file is generally employed without regard to econorny.

Files are tools of ancient origin, and after centuries they have come down to the present in practically the same form, rvith the exception that they are now finished better. The l-ristory of the file goes back beyond the prehistoric _age, the eirliest files to which reference is made having been composed of the skins of certain fish. Even today in Greit Britain old-fashioned carvers use the skins of the dog-fish to smooth their work. There were files used by prehistoric man which were made of bronze. That there ivere different shapes for different varieties of work is indicated by reference to the Bible; for example, I Samuel XIII. 2l which reads: "They had a file for the mattocks, and for the coulters, and for the forks, and for the axes, and to sharpen pads."

That-steel files are of antique origin is indicated by re{erenci to the Eighteenth Century French Encyclopedia, which gives a number of illustrations, which differ in few respects from the moderh tool.

It is not so many, many years ago that all files vl'ere cut by hand, but at present more than 90 per cent of the files made are machine cut. Although this is practically a recent development, history shows it is by no means new. In the eighteenth century Raoul, a Frenchman, cut files bL machinery, and in 1836 a machine patented by Captain Ericcson was used in England.

It is contended by manufacturers that finer quality files are made by machinery than it is possible to cut by hand. Some special machine cut files have more than 180 teeth to the inch, with cuts scarcely discernible to the eye.

There are many different files for different kinds of rvork, but the most common types include mill, flat, hand, round, square, half-round, taper saw, slim taper, also various styles of rasps.

It is known that modern methods of file manufacture employed by Simonds Saw and Steel Company, Fitchburg, Mass., result in quality files unequalled. Much depends on the quality of the steel used. This steel is received from the Simonds Steel Mills in bars several feet in length.

The first operation is to shear the bars into the necessary lengths to form the file blanks. The tangs and the points of the blanks are formed by means of power hammers, rolls, presses, etc. The blanks are then annealed, after which they are smithed or straightened, a necessary operation so as to sehd the blanks in proper condition to the grinding machine.

The blanks are next ground on wet grindstones, to remove all oxide and scale from the surfaces; this operation also corrects minor inaccuracies and gives greater uniformity of shape. There still being slight irregularities in the surfaces, the blanks are stripped or draw-filed to true surfaces. Depending upon their kind, files are either single cut or double-cut. Follow a double-cut flat file: the blanks go to a file-cutting machine, where the first set of teeth (over-cut) on the sides are cut; corners are then struck off on an emery wheel, and the blanks returned to another cutting machine rvhere the teeth on the edges are cut. The over-cut sides are now stripped, (draw-filed) to remove the sharp edges, after which they go to another cutting machine, and the finishing teeth (up-cut) onthe sides are (C."tt"t.d t" P"C. 56)