The common file, as every workman
knows, is an implement, the flat or curved surfaces of which are
notched or serrated in such a manner that, being rubbed on the wood, ivory, metal, or other hard substance for which the
tool is intended, a surface of more or less smoothness is
Files are made of bars of steel prepared in a peculiar
manner, it being necessary that the file should be formed of the
hardest possible metal, or else its working surface would be
speedily worn away.
The steel is therefore rendered
harder than usual by means of a process known as double
conversion; the metal thus prepared being said to be doubly
converted. Small files are generally made of cast-steel, which
is for this purpose preferred to forged steel, on account of its
fineness and quality. The larger kind of files are forged from
bars of steel, which have been beaten into the requisite shape
by means of the tilt-hammer. The largest kind of flies, rather
formidable looking tools, are forged from the barsteel, without
the latter undergoing the preliminary process of tilt-hammering.
files are then shaped the square and flat ones by means of a
common anvil and hammer; those of a circular, half-round, or
triangular form by means of bosses or dies, made of the
corresponding shapes, fitting into grooves made for them in the
The surface of the file thus
prepared is perfectly smooth, but it has to undergo another
process that of softening before it can be serrated or toothed.
This softening, or lightening, as it is technically called, is
effected by placing a number of blanks, as the uncut files are
termed, in a large brick oven, made perfectly air-tight, to
prevent the steel from becoming oxidized.
The fire is made to play round the
oven until the blanks are perfectly red-hot, when the heat is
relaxed, and the oven gradually allowed to cool. On the
perfection of this process depends much of the value of the
file, and the labor of the worker. If the metal be too soft, the
indentations may be too heavy and irregular if it be too hard,
the workman will find much of his labor fruitlessly expended.
After being softened, the blanks
are carefully ground and smoothed down to the requisite shape,
after which they are passed to the file-cutters.
File-cutting is a curious and
interesting process. The cutting-rooms are generally long, low
apartments, with as many windows as possible, it being essential
that the workman should have plenty of light, so as to
immediately detect or prevent any flaw in the cutting. The
work-benches are placed along the wall, just below the windows,
each file-cutter sitting upon a stool, or astride a
saddle-shaped seat, immediately in front of the bench.
Before each workman is small anvil fastened to the bench in such
a way that it can be instantly removed if required. The cutter
ties one of the blank files upon the anvil, securing it from
slipping by means of a strap which passes over the ends of the
file, and which is held tightly in its place by the weight of
his foot. He then takes a peculiarly shaped hammer and a short
chisel, rather broad in appearance, having a carefully ground
edge, and formed of extremely hard steel.