The purposes for which files and rasps may be
used are legion, yet the principal file makers are prepared to
make, in addition to regular goods, anything in steel files for
use in any industry, regardless of shape, cut, grade of steel or
temper, provided the sizes of the orders warrant.
The representative manufacturers make hundreds
of kinds of regular files, and several thousand when special
files are included. The kinds best known embrace mill, fiat,
hand, square, round, half round and three square, with flat,
half-round and cabinet rasps, horse and shoemakers’ rasps. The
term “flat-file” is not given because it is flat, but
particularizes a type of file, as mill, flat and hand files are
all in appearance fiat files.
Machine Cut Files Most Largely Used
Manufacturers of machine-cut files say that
finer quality files are now made by machinery than it is
possible to make by hand, some of which, machine made for
special purposes, have more than 180 teeth to the inch, with
cuts scarcely discernible to the naked eye. Hand-cut files are
still made, and are sometimes preferred without regard to cost,
and undoubtedly possess advantages. People often wonder how a
file cutter manages to space the numerous grades of hand-cut
files so uniformly with hammer and chisel, guided only by the
Actually, when cutting by hand the workman is
guided not so much by sight as by the “feel with chisel and
weight of hammer.
Types, Forms and Purposes of Files
“Flat files” taper from near the center to
point, are narrow and slimmer at the point, and double-cut on
the side with edges single-cut. Flat files are commonly used by
mechanics on coarse and rough work.
“Hand files" are made from a heavier blank than
flat files, tapering in thickness from the center to point; are
parallel in width and double-cut on sides, one edge single cut
and the other edge “safe” (no teeth), so that the file is usable
in corners without filing both sides of the angle. They are made
in the same cuts as flat files, and are used by machinists and
engineers for finishing flat surfaces.
“Square files" are forged taper. Some are made
the same size from heel to point, or blunt, and known as “square
gulletting" files, single-cut on four faces. These are used
where other files are impossible on account of their width,
i.e., for filing apertures, dressing out square corners, etc.
“Half-round files” taper from near center to
point, are double-cut on the round and flat sides, and are used
for general machine shop work.
“Mill files" taper from near center to point;
are thinner and narrower at point; some are made with one and
others with two round edges, single-cut on the sides and edges.
This type is commonly used for filing mill saws, sharpening
planer knives, mowing and reaping machine cutters, and for
certain kinds of mechanical work such as draw-filing, lathe
work, etc. Their chisel teeth leave a comparatively smooth
surface, which double-cut point teeth do not, although the
double-cut point teeth out faster. A few mill files are
‘Round files" are usually tapered, and owing to
their form are frequently referred to as rat-tail files, though
some are made of uniform size from heel to point and are
single-cut. Round files are used mainly for gulletting,
enlarging holes, etc.
“Three-square files" are made from
three-cornered steel, usually tapered, double-cut on all three
sides. The edges are uncut and left very sharp. Occasionally
they are made single-cut, also blunt or parallel, and are
particularly serviceable for cleaning out sharp angles and
square corners, filing cutters, taps, etc.
“Taper saw files" are likewise made of
three-cornered steel, usually are forged tapering, but differ
from the three-square file in that they are smaller, generally
single-cut, have teeth on the edges as well as sides, and are
not cut quite to the point. They are also manufactured
double-cut as well as blunt or parallel.
"Tapers" are used for filing band saws and all
small saws. The double-cut tapers having point teeth, file
faster than the single-cut, but the latter having chisel teeth
Some tapers are tapering at both ends without
tang for handle, are single-cut at both ends, which makes two
files in one piece. These are termed “double end” or “reversible
tapers." Taper files are really divided into three
classes: the regular taper file, the slim taper and the extra
The slim taper file is of the same general shape
as the regular taper, but is made of a smaller section of steel
for the same length. They are preferred by many on account of
the greater sweep of stroke obtained from the same thickness of
file, and for this reason, in fact, they are taking, to a great
extent, the place of regular taper files.
The slim taper file is particularly adapted for
filing fine tooth saws. A file similar to the slim taper file,
but made on more slender lines, is the extra slim taper referred
“Knife files” are tapered and resemble in shape
the blade of a pocket knife; they are double-cut and used for
filing the inner angles of the sear, main springs of gunlocks,
and works of similar shape.