The copper country evening news. [volume] (Calumet, Mich.) 18??-1907, 1897-10-08
HANDMADE FILES.
AN INTERESTING DESCRIPTION OF A
DELICATE PROCESS.
WOrkmen Become So Accurate That They
Gould Go on IL They Became Blind--Me-
chanics Held 1t to BE an Art In Which
Machinery Could Not Compete.

Soufu NV tomPetes
Rasps and files in the hands Of a first
Glass mechanic rise TO the dignity of tools
Of the first order in a machine shop. TO
file square Is test of skill which has
caused many a braggart TO lower his crest,
and AN l wise hand Is a treasure in a
shop where finishing is done on the bench.
To file square means 10 file true; To finish
the face of the work without marring it
with scratches and rounding surfaces, and
To do this rs "a regular everyday thing Is
an art to be won only through practice
and long experience Files ruin thousands
Of dollars worth of work and files add
thousands of dollars TO tie value of manu-
featured product.
In some of the machine shops of Chica-
go are gray haired mechanics who have
worn overalls for 40 years and more. They
remember well the time when machine
made files were held up to- ridicule and
scorn and when all first class, well known
makes of files were cut by hand. Some of
these old fellows still insist that machine
made files are not and never can be Us
good as the files which are cut by hand,
and they carry this prejudice to such an
extent that they declare they cannot do
good work with the machine cut files.
III WOulu De ulICulU lOr lltln 10 lcll til6
difference between the two makes of files
for within comparatively few years ma
chimes have been making files that cannot
bo approached by the most expert file cut
tiers of Sheffield Files and many of them,
are still cut by hand, and a file cutter is
probably the most expert user of ham
mer and cold chisel in the industrial world.
Files and rasps are made of steel which
varies from the clustered" steel for the
poorer quality of files to the best crucible,
or least cast steel, for the higher grades.
The blanks are prepared for the file cutter
by forging the "tang," or tapered point
for the handle, and shaping the steel TO
the proper form under die or press. The
blanks are thoroughly annealed or soften
ed and are perfectly clean and free from
scale when laid on the bench of the work
man who cuts the teeth.
file cutter generally works on the
same kind of cut year in and year
out. This gives him mechanical perfec-
ton which cannot be secured in any other
way, and it is said that "a wOrkmans
hand becomes so accustomed To the spac-
ing that were he to become blind he could
cut just as well.
Files are made of many forms TO suit
the great variety of work which they are
called upon to do, but the "cuts" which
give coarscness and 1lneness to files are
comparatively few. They are known as
trough, ""bastard, 4" smooth" and dead
smooth" These are the common "cuts."
Floats" are single cut files, and double
cut files are made by crossing the first
cut with second cut, thus changing the
parallel, unbroken cutting edges of the
floats into numerous points.
When u face, or one or more edges on q
file is left uncut, it Is said TO be 'safe."
No matter what the form of the file is,
whether fiat, square, round, half round,
rat tail, three square or knife edged, the
cutting is done the same way. A short,
light, steel cold chisel, with Broad
straight cutting edge Is used. The ham,
mer is a curious looking affair, for it is
curved somewhat, and the handle is in
serted well toward the smaller end. The
hammer weighs from one to six pounds.
In striking the workman gives peculiar
pulling blow which raises the "bur" and
gives the particular cut characteristic of
files, and it was this cut that for nearly
200 years prevented inventors from design
ing machinery which would cut file
equal to the hand cut article.
The workman sits on low bench which
COllltS OuU ITOlll a lOuS Wllc ipOlOiO
him is his anvil, usually stone block or
"a slab of iron. The blanks are held in
place by straps which pass over the tang
! and point, and then form a loop or stirrup
under the anvil The workman puts his
foot in the loop, and thus holds the blank
secure while he Is cutting it. He holds the
chise between the finger and thumb of
the left hand, and after each cut moves the
blank slightly for the next cut. He does
this by lifting the chisel over the bur and
then pressing the point of the tool against
the raised edge just out, at the same time
loosening the strap SO that the blank can
be moved.
In cutting small files or smooth or dead
smooth files the hammer blows, movement
of the chisel, loosening the straps, moving
the blank, Tightening the strap and strik-
ing the next blow are done so rapidly that
they are nearly simultaneous. The float
cut is made first, and then the second cut
Is made. In making the second cut the
workman strikes the chisel with less force,
thus making a shallower cut If the file Is
to be cut on the other side, the cut side is
laid upon plate of lead or pewter to pro-
tect the cutting edges. If the file Is other
than q fiat shape, the lead or pewter Is
grooved or followed out to fit the shape.
After cutting, the files are hardened, for
the annealing makes the steel so soft that
the first use of the file would bend the cut
ting edges. Some files are curved before
being tempered. This is done by heating
the cut files to a dull red and bending
them to the required curve over wooden
block with a wooden mallet. The files to
DO hardened are first covered with mix
ture of salt and some sort of carbonaceous
substance. This covering serves twofold
purpose-it prevents the teeth from oxida.
tion and from losing the carbon in the
steel, and by fusing indicates the proper
heat for tempering 1t also serves to pre-
vent cracking when the file is suddenly
plunged into the cooling liquid which
gives the file the temper.
Naturally heated file suddenly cooled
will warp more or less according to its
form. This is prevented by giving the file
'set" in the other direction before 1t is
tempered, so that the tendency to warp
actually straightens the file. When the
steel has reached the proper heat, the file
is lifted from the fire by the tang and sud
denly immersed in cold water, and before