The Ely miner. [volume] (Ely, Minn.) 1895-1986, 1899-06-07
MADE OF GRAPHITE.
Ordinary Lead Does Not Enter Into
the Composition of
Pencils.

The first thing to be said about lead
pencils is that they are not lead pencils
at all. Once upon a time sticks of lead
wer used for making marks on paper
and wood, and the name has survived,
though nowadays all the pencils are
filled with graphite, or plumbago. This
mineral is found in only few places
in the world-in Cumberland, England,
along the Laurentian ranges in the
province of Quebec, and at Ticonderoga,
Vt. The largest mines on this con-
tinent are at the latter place.
The graphite is taken in the lump
from the mines and carried to the re-
ducing MILL where it is ground or pull
verified in stamp mills under water.
The fine particles of graphite float away
with the water through number of
tanks, collecting at the bottom of these
reservoirs. 1t is packed in barrels in
the form of dust anG sent to the factory,
-uhara tens of thousands of lead pencils
are turned out every day. The pulver-
lied graphite is so fine that it really is
dust, dingy in color and smooth and
oily to the touch. 1t is divided into
various grades of fneness by floating
it on water from one tank to another
The coarse dust sinks to the bottom of
the first tank, the next finer to the bot
tom of the second tank, and so on down
the line, the finest powder for the finest
pencils settling in the last tank
In another series of tanks the Ger
man pipe clay, which is mixed with
graphite to secure the different grades
of pencils from very soft to extra hard,
is graded in the same way, by floating.
The finest clay is mixed with the finest
graphite, being ground together be-
tween stones, and the hardness of the
pencil is secured by increasing the pro-
portion of clay in the mixture.
For the medium grades seven parts
by weight of clay are mixed with ten
parts of graphite. After the graphite
and clay are ground together the mix
ture is put in canvas bags and the water
is squeezed out under a hydraulic press,
leaving mass the consistency of putty.
The plaster is placed in a forming
press, which is a small iron cylinder,
in which a solid plunger or piston works
up and down. A steel plate having a
hole the size and shape of the lead
is put under the open end of the cyl
inder, and the plunger pressing down
forces the graphite through the hole,
making continuous thread or wire of
graphite. As long as this thread is
moist it is pliable, but it becomes brittle
when dry, so it is handled rapidly. 1t
is cut into three lead lengths, straight
ened out, and then hardened in cruel
BILE over a coal fire. The leads when
taken from the crucibles are ready for
the wood, which is pine for cheap pen
ellis and cedar for more expensive ones.
When the strips of wood are received at
the factory they are run through ma
chine which cuts in each one six
grooves, round or square, and at the
same time smooths the face of the wood.
The filling of the strips is done by girls.
The first one takes a grooved strip of
wood in her left hand and bunch of
leads in the right. She spreads the
leads out fan-shape, and with one mo-
ton fills the six grooves with leads.
Next to her sits anotl er girl, who takes
the filled strips and quickly and neatly
lays on another grooved strip which has
just been coated with hot glue by a
third girl. The filed and glued strips
are piled upon each other and put in a
press, where they are left to dry. The
ends of the strip are evened off under
;andpaper wheel, and then the strips are
fed into a machine which cuts out the
individual pencils, shapes them and de-
livers them smooth and ready for the
color and polish in six streams. The col
bring is done with liquid dyes, after
which the pencils are sent through the
furnishing MISUNDERSTOOD and Home.