In the sharpening of saws, a great many files
are used. During the War of the Rebellion, Henry Disston & Son
(this being the firm name at the time), unable to obtain files
which would give satisfaction, found it necessary to make files
for their own use. This becoming known, it was not long
before requests were received from customers that they be
The demand increasing, it was decided to enter
the field of filemaking and in 1866 a plant was equipped and
additional skilled workmen employed to turn out high-grade
files. As with his saws, Henry Disston always wanted to
turn out the best, so he gave his attention to the production of
a file that would be superior in quality, shape, and cutting
power of teeth. Although his first files were made by
hand, he realized early the necessity of machines in the
production of perfect files.
none of the machines so far invented were considered exactly
perfect, the Disston Works carried on extensive experiments for
the production of file-cutting machinery that would be adequate
to meet every demand. Their efforts were successful.
In 1877, the Disston Works started to make files
by the aid of their own machines. Constant improvements
were made from year to year until today the teeth of Disston
files are cut upon the most perfect file-cutting machines.
In 1866, the Sheffield Telegraph, of Sheffield,
England, held a contest to reach a final decision as to whether
machine or hand-cut files were best. One side of each file used
was machine-cut, and the other hand-cut.
After exhaustive tests
the firms trying out these files without a knowledge of which
side was which, decided in favor of the machine-cut files, which
forever settled a controversy that had been waged for two
As has been shown in the foregoing history of
the file, many of the present forms of the file were
substantially originated in the earliest days of its history.
These have been modified and added to as the knowledge of file
manufacture increased and new and different uses were
discovered. There are today a large variety of files being made.
These various forms will be taken up in the later parts of this
article, but we will first consider the making of the modern
file. In describing its manufacture the word file is used in its
broad sense as applied to both files and rasps, irrespective of
either size or form.
Disston Company Make Greatest Variety of Files
Although not the oldest manufacturers of files
in this country, the Disston File Works today is well equipped,
and turns out the greatest variety of files made. A general
description of the Disston methods therefore, will give a clear
idea of the manufacture of the modern file.
There are, of course, quite a number of points upon which the
high grade file depends for its superiority.
The principal ones are:
Tough steel of a high grade suitable for
Proper forging and annealing.
Sharp and well-formed teeth.
Careful inspection at every stage of the
The real basis of the file is the steel. All
manufacturers endeavor to obtain the very finest steel possible
for the purpose, but the quality of the steel is bound to vary
to some extent unless the manufacturer has some way of
controlling the output. Steel for making files requires a high
percentage of carbon to obtain the requisite hardness.
This carbon-content is apt to vary unless the
"mix" is carefully regulated.
Make Their Own Steel
Henry Disston & Sons began to make crucible
steel as early as 1855 so that when they took up the manufacture
of files they were in a position to obtain steel of a high and
uniform quality. The Disston Steel Works, which includes the
melting department, rolling mills, steam hammer shop, and
trimming room, occupies several commodious buildings. There are
laboratories where the chemical and physical tests of the steel
are made. Constant experiments with proper ingredients to
maintain and enhance its quality are conducted in connection
with the steel works.
After the special steel has been carefully and
properly melted, it is poured into moulds. When the steel is
cool, the mould is removed and the ingot which has been formed
is then turned over to the rolling mill, where it is reheated
and rolled into large bars. These bars are then cut into smaller
pieces, and the pieces are again heated and run through
different size rolls, which reduce the diameter, but increase
the length. The last roll through which the steel passes reduces
it to the particular size and imparts the shape or form desired,
such as round, half-round, flat, three-square, etc., each
thickness and shape being specially rolled.
It may be of general interest to learn that in
rolling steel for a 14-inch flat file, which is approximately
1-7/16 inch wide by 3/8 inch thick, the bar, as referred to
above, measures 4 inches by 4 inches, 24 inches long. This is
heated and rolled through one roll after another continuously,
until it is reduced to the size and shape required for the file
and is then approximately 50 feet in length. This long bar or
rod of steel is cut in ten or twelve-foot lengths and sent to
the file works, where it is cut into multiples the length of the
file to be made.
The first step, then, in the actual manufacture
of the file is the cutting of these long rods of steel into
pieces or sections of the required length. The pieces of steel
thus formed are termed file blanks.