The Indianapolis journal. [volume] (Indianapolis [Ind.]) 1867-1904, 1899-05-05
NOT LEAD" PENCILS.
Graphite 10 the Substance. Mixed with
German Pipe Clay.

ScnOOl ana ftOmt.
The first thing to be said about lead PEN
ellis is that they are not lead pencils at all;
Once upon q time sticks OF lead were USED
for making marks on paper and WOOD, ana
the name has survived. though nowadays
all the pencils are filled with graphite or
plumbago. This mineral Is found In only a
few places IN t ne Tor,pr,ni ranges in
the province OF Quebec and at I1conderoga,
VT. The largest mines on this continent are
The graphite is taken in the lump from
the mines and carried 10 the reducing mill.
where 1t Is ground or puiverizeo III stamp
mills under water. The fine particles or
graphite float away with the water through
a number of tanks, collecting at the pot
tom of these reservoirs; III IS packed IN oaI-
rels in the form of dust and sent TO the
factory, where tens OF thousands of lead
pencils are turned out every day. The pull
verified graphite is so fine that II really Is
TO the touch. 1t is divided into various
grades of fineness by floating IL on water
from one tank 10 another. The coarse dust
sinks to the bottom OF the first tank. the
next finer TO the bottom 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 German pipe
clay. which is mixed with graphite 10 Sc
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 between stones, and the hardness
of the pencil is secured by increasing the
proportion of clay In the mixture.
For the medium grades seven parts oy
weight of clay are mixed With ten parts OF
graphite. After the graphite ana Gay are
ground together the mixture Is put IN cam
vas bags and the water Is squeezed out Tn
der an hydraulic press. leaving a mass the
consistency of putty. The plaster Il paced
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 -
put under the open end of the cylinder. ana
the plunger pressing down forces the graph
tie through the hole. making a continuous
thread or wire of graphite. As long as THIS
thread Is moist IL is pliable, but II becomes
Brittle when dry. so IL Is handled rapidly ~
is cut into three lead lengths. Strengthened
out. and then hardened in a crucible over a
coal fire. The leads when taken from the
crucibles are ready for the wood. which is
pine for cheap pencils and cedar Tor more
expensive ones. When the strips OF wood
are received at the factory they are run
through a machine which cuts IN each one
six grooves. round or square, ana AT the
same time smooths the face of the wood
The filing OF the strips IL done by girls.
The first one takes a grOoved strip or wood
in her left hand and a bunch Of leads In the
right. She spreads the leads out In fan shape
and with one motion she nils the six grooves
with leads. Next 10 her sits another 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 filled 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 of under a sandpaper wheel
and then the strips are fed into a machine.
which cuts out the individual pencils. shapes
them and delivers them smooth and ready
for the color and polish In six streams. The
coloring is done with liquid dyes, after
which the pencils are sent through the warm
ishing machine.