Savannah courier. (Savannah, Tenn.) 1885-1979, 1886-09-09
LEAD PENCILS.
The American and Foreign Process
of Making Them.
Daily Consumption by This Country, q
Quarter of a Miilion-Graphite and Its
Peculiarities-Forclng the Coll
Filling the Leads.

The consumption of lead-pencils in
this country is estimated at 250,0O0 a
day. This is at the rate of one per day
to every l60 of population. or about
$4,000, 900 year. Graphite, which is
the softest substance dug from the
earth, is taken in the lump direct from
the mouth of the mine to the reducing
mill. Here il is pulverized by stamps
under water, the particles floating off
with the water through a series of
tanks. 1t comes to the factory in bar
rels, in the form of dust The powder
is lusterless and of a dingy color. 1t
is finer and softer than any -four, and
can be taken up in the hand just as
water can, but is hardly retained more
easily than water is. If one attempts
to take pinch of it between the fore
finger and thumb it is as evasive as
quicksilver, and the only sensation left
is that the flesh is smoother than be-
fore.
The first process in manufacturing is
to separate the graphite dust further,
according to fineness. It's mixed with
sufficient water to run very freely, and
is then turned into a hopper, from
which the water runs slowly through
q series of tubs. The coarsest and
heaviest particles settle to the bottom
of the first tub, the next coars-
est and heaviest in the next, and so
on, the movement of the water being
made very gentle. On reaching the
last tub the powder, being twice as
heavy as water and sinking in it if un-
disturbed, has so far settled that the
water discharged at the top is nearly
clear. After the flow is stopped and
the powder allowed to settle the clear
water is withdrawn by removing sue
cessively, beginning with the upper
one, number of plugs inserted in
holes in the side of each tub, care be-
ing used not to agitate the contents so
as to disturb the deposited dust. This
being done properly, the deposit is
removed through the gates at the bot
tom of each tub. The separation is
thus performed, by this ingenious
process of floating" more perfectly
than it could be by any direct handling,
dry treatment being wholly imprac-
ticable. For the finest pencils the de-
posit from the last tub only is used,
but for ordinary and cheap grades that
from the two before the last will an
swer.
The graphite is now ready for the
clay. This is peculiar pipe clay,
from Germany. After being subjected
to the floating process, the finest is
mixed with the graphite, in proper
tions varying according to the degree
of hardness required. The more clay
used the harder the pencil. For me-
dium grades the proportion is about
seven parts clay to ten graphite by
weight. The graphite and clay are
mixed together with water, to the con-
sistency OF thick cream, and the mkt
ure is fed to the grinding mills, which
consist of two flat stones about two
feet in diameter, placed horizontally,
only the upper one running. Between
these the mass is ground like paint, fol
the finest pencils as many as twenty
four times, thus securing the most per.
feet strength, uniformity, and freeness
from grit in the leads. After grinding
the mass is inclosed in stout canvas
bags, and the clear water forced
out by hydraulic pressure until it be.
comes thick dough. 1t then goes to
the forming-press. This is simply O
small vertical iron cylinder, having 8
solid plunger or piston driven by &
screw. A plate is inserted in the bot
tom. having an opening of the shape
and size of the lead desired, and tn,
graphite is slowly forced through tn,
ho}e., exactly as water is forced through
sytinge, coiling itself round anC
round ike coil of wire on boart
set beneath the press. The coils taker
up at intervals, "rove" off straight b,
the hands into lengths sufficient fo
three leads, which are Strengthened
out laid in order on a board, an'
pressed fiat by putting a cover owe
them. They are finally hardened b,
placing them in crucible and bakin.
in kiln. The handling must be dom
expeditiously, as the leads begin dry
ing Immediately and become brittle a
they dry; but on first issuing from tn,
press they are so plastic that knot
may be tied loosely in them.
The leads are now ready for thei
wooden case. For the cheapest penci
pine is used, for the common grades al
ordinary quality of red cedar. AT tn
saw-mills the cedar is cut int
blocks about seven inches long
and these are sawed into strips abou
three and half inches wild
and three-sixteenths of an incl
thick. The pencil consists of two part
glued together. with the lead be
tween. Each strip is wide enough t
make the halves of six pencils. Tn
pencils are made six at a time, an,
imperfect strips are put together so a
10 make q full strip out Of the parts
When these boards (which are nov
ready for shsping) reach the factor
they are first passed in continuou
line under cutter, which cuts 81