The Andrew County Republican. [volume] (Savannah, Mo.) 1871-1876, 1876-07-27
About Lead Pencils.

1t Will perhaps surprise some OF our
readers, says the american Grocer,
when we state rs a positive fact that
lead pencils contain nothing of lead ex-
cept in the name. Yet such is the truth.
Leaf pencil is, in fact, as much Il mis-
homer as it would be t. call a horse n
cow. Red lead is an oxide of lead, and
white also n carbonate of that metal,
but the black lead used in pencils is
neither n metal nor n compound Of
metal. 1t is plumbago or graphite, one
of the forms OF carbon.
Formerly the square pieces of graph
lite, which form the marking portion of
the pencil, were sawed ont of large
masses of that material but when pen
ellis came into such universal use it was
found that this method of procedure
necessitated so much waste, that it was
quickly discovered that some other pro-
cess must be used in order to utilize the
wastage. In such cases the want is
seldom felt before some ready inventors
brain supplies the remedy. So it was
here. After the experimenting neces-
sary to bring any invention down to a
practical working basis, the following
method was matured:
The fragments of graphite are ground
fine, calcined and mixed with pure clay.
This clay has been prepared by difFus-
ing it through water, allowing the
coarser particles to settle, drawing off
the milky fluid from the top and letting
it settle again. This latter sediment is
exceedingly fine and plastic, and after
being dried on linen filters is fit for use.
1t is then mixed with powdered graphite
in various proportions, according to the
degree of hardness required in a pencil
two parts of clay to one of graphite
being used for a fine, hard grade, equal
parts for Il soft one, and intermediate
mixtures for the grades between.
The materials, after being mixed, are
triturated or kneaded with water until
they are about the consistency of dough.
This is pressed into grooves in IN 9th
erwise smooth board, dried in the mold
by a moderate heat, then taken u and
baked in covered crucibles in n furnace.
Sometimes the dough is compressed in
a surong receiver and forced out through
q small hole in Il thread of the shape
required, then dried and baked as
above.
The grade of lead depends also part.
ly upon the degree of heat to which il
is exposed in the furnace. Leads in
tended for very fine work, like archi,
tectural drawing, ETC., are reheated af
ter the baking and immersed in melted
wax or suet.
The wood used for all the better kinds
of pencils is the Florida red cedar. L
is first thoroughly seasoned, then saw
, ed into strips, dried again, and then Gu
into strips of proper size for pencils
They are grooved by machinery, tn,
leads are glued into the grooves and tn,
!, other half of the wood glued on. Afte,
being dried under pressure, they ar,
rounded or otherwise shaped by a kind
, of lathe or cutting machine, then polish
t ed by another operation, and sometime
! painted or vanished by a third, which
feeds the pencils from a hopper ant
turns them around under the brush
They are next cut the right length by
i circular saw, and the ends made smootl
\ by a drop knife, after which they ar,
Q stamped by a heated die and sent to tn,
/ packing room to be packed for sale.