File-Making by Hand and Machinery

  from "The Manufacturer and Builder"  November, 1889 

    But few tools can lay claim to as great antiquity as the file.  So very old is it, indeed, that no mention can be found in either profane or sacred history of its invention, for it antedates written history; but in the Bible, in second Samuel, the thirteenth chapter and the twenty-first verse, is to be found the following: "Yet they had a file for the maddocks, and for the colters, and for the forks, and for the axes, and to sharpen the goads."  This was 1093 years before the advent of the Christian era, and there is every reason to believe that the file was in use before this time.  Certain it is, that from that time on, there are numerous proofs to show that the file became more and more in general use as the years went on.  In the sixteenth century it had become so common that all reference to it was a purely matter-of-fact way, as when Burnett, in his "History of the Reformation," describing how Sir Edward Grimston escaped from prison, thought it only necessary to say that the cell bars were cut apart with a file.  It has only been within the past quarter of a century that there have been placed in operation any marked improvements in the process of manufacturing files; and even yet there are many mechanics who still insist that files made by the methods of a century ago are superior to those made by the more modern methods of machinery.  Up to within late years this opinion has had all points of fact in its favor, and even now it may have some.  A description of the two processes - that is, hand and machinery, will, therefore, be of interest.

     Take the former, or hand process, to begin with. The steel is first rolled, or tilted, into bars of a size as nearly as possible to the sections required.  The sections bring to the steel in the rough, which are cut from the bar into about the length and diameter of the file required.  They are then annealed with great care by placing them in annealing ovens heated by charcoal, coke or anthracite coal, until they are of a cherry red, and then allowed to cool gradually.  This sufficiently softens them for the chisel cutting, but very frequently after being taken out of the oven it is found that the heat has bent or warped them.  Should this be the case, they are forged into shape again.  They are now filed or ground, the grinding being done on a huge stone, six feet in diameter, the workman sitting almost astride of it and holding the steel directly on the stone with both hands.  In olden times, and even in years not long past, this was a dangerous process, as the stone would sometimes break while in motion, with fatal results to the workman.  These accidents are rare in this country, owing both to the care exercised by the grinders and the superiority of the stone used.  After the blanks are ground, they are "stripped" - that is, they are filed down to the true surface to remove all irregularities.  They are now ready for the cutter, who sits astride a bench in front of the block or anvil, across which rests the file.  It is held firmly in place by a strap across either end, into the lower loops of which are placed the cutter's feet, like stirrups, the weight of the legs thus firmly holding the bar in place.  The tang ( the part to be inserted into the handle ) points toward him, and, after slightly greasing the "blank," he is ready to cut the teeth.  In his left hand he holds a small chisel, the edge of which always exceeds the width of the file, and placing it on the "blank," with an inclination of from 40 degrees to 55 degrees, according to the character of the file to be made, he gives it a sharp blow with the hammer in his right hand.  An indentation in the farthest or small end of the file in thus made, the indentation naturally inclining toward him.  This, of course, leaves a ridge, or a tooth, slightly thrown up above the surface, and, following this as a guide, he places his chisel alongside of it and strikes another blow with his hammer, and this is continued until the teeth are cut the full length of the face of the blank.

     An average workman will strike from sixty to eighty of these blows per minute.  All this time the file is resting on a thin sheet of pewter, or a bed of pewter and lead mixed together, so that the opposite side of the file will not be injured.  In cutting round, or half-round files, the indentations are made very narrow, say about one-tenth of the circumference, and run in a straight line from point to tang.   Then the next indentations are cut in the same way, but shaped differently, the chisel being applied as a tangent to the curve.  In cutting cross teeth, the same methods are followed - that is, indentations are made over indentations.

     The files are now ready for tempering, or hardening.  They are first covered with a paste, made of powdered cows' hoof and other material, to protect them from damage while heating, and are then heated to a red heat in molten lead, which gives them a perfect, even temperature, and plunged into strong brine.  From the latter they are removed before they are entirely cold, so that they can be straightened if necessary.  Following this, they are treated in a muriatic acid bath and then a lime-water bath, the first to remove all oxides and surface dirt, the latter to remove the acid.  The tangs are then softened, after which they are brushed with oil, and they are ready for packing.

     Two hundred years ago attempts were made to cut files by machinery, but with no encouragement until about 1858.  Less than thirty years ago a company, with immense capital, was organized in Birmingham, England, to operate the file-cutting machinery invented by E. Bernot, a Frenchman, but the effort soon proved a failure.  The same result followed the Prestons, of Manchester, Eng., and the British Patent Hardware Company, of the same place, the machinery of the latter being the invention of an American.  Numerous attempts were also made in Sheffield, Eng., but partially owing to imperfections in the cutting machines, and the opposition of workmen to machinery of any shape or form, the efforts proved abortive.  France had also had her file-cutting by machinery enterprises with more or less success.  This country, however, was more fortunate in this regard, and is quoted in the "Encyclopedia Britannica" as the first nation ever clearly to demonstrate that perfect files could be made by machinery.

     In the fifties, the American File Works made files by machinery, at Ramapo, N.Y. but only remained in business for a few years.  An attempt of the same kind in Hartford, Conn., in about 1857, did not succeed.  Then closely followed the Whipple File Works, of Ballard Vale, Mass., in 1858, the Weed File Company, and others.

     The most successful was the Nicholson File Company, of Providence, R. I., which was organized in the spring of 1865, with W. T. Nicholson, the inventor of their machinery, at its head.  The substantial brick buildings were planned to admit of enlargement from time to time, as might be required.  One of the first steps taken was to ascertain what had been done, not only in America, but in the old country, both in files and steel, and to this end their agent spent several months in Europe, with full instructions to purchase such machinery as might be thought worthy of adoption.  These works now turn upwards of 1,500 dozen files per day, and their success is absolute proof of the merits of the machine-cut file.  The machinery used by this firm is so arranged that it will produce a file with teeth, in their spaces, conforming to the hand-cut file.  The article produced, the company saw fit to call the "increment cut file," the word "increment" meaning increase.  These files are not cut a uniform depth or space, and no two spaces can be found exactly alike in the entire length of the side.

     A file machine, it should be understood, is a machine that moves a "blank" quickly upon a bed, with a chisel rapidly falling upon the blank as it moves, and making teeth or indentations.  The clearest description that could be given of it, is that it is hand-work operated by machinery, for one hand of the machine slides the blank along, while the other sets the chisel and strikes the blow with the hammer.  The objection to machine work, however, by those who claim to entertain any objection, is that it is so accurate that the teeth are cut regularly in rows, and of a uniform depth, a thing to be avoided in making a perfect file.  In making them by hand, however, this accuracy or regularity, could not be obtained by the most skilled workman, even if it was desirable, for the force of his blows cannot always be the same, nor can he always place his chisel exactly in the same position.

     In speaking of the variance between their increment files and files with the regularly cut teeth, the Nicholson File Company very clearly explain by saying that the difference between this and the perfect regularity of the old machine-makes must be apparent, particularly in the double-cut files, as in the one case the files cut with such extreme regularity, when put in use, will in the first inch of its movement produce channels or grooves, and the grooves will continue to be made deeper as the file shoved along, thus producing that "grooving" and "chattering" so often complained of, while in the "increment-cut file" the grooves made by the movement of the file for the first inch will have their sides cut away as the file is moved toward the "tang" or handle, and vice versa ; and while it is cutting as fast as it's points will permit, it is also said to cut smoother than the best hand-cut of the same coarseness.  The irregularity spoken of consists not only in the spaces between each tooth, but also in the heights of the teeth themselves, thereby completely removing the objections hitherto argued against machine files.

     Rasps are also made both by machinery and by hand, the chisel for making them however, being in the form of a three-cornered or triangular punch.  The other processes are precisely as in file-making.

    Notwithstanding the great number of files made in this country, a file is often made over, or sharpened- as often as three or four times, many small concerns doing nothing but this.  The word "sharpen" in this case is misleading, for in reality the old teeth are ground off and new teeth chiseled in.