Thomas County cat. [volume] (Colby, Kan.) 1885-1891, 1886-09-02

Filling the Leads.
The consumption of lead-pencils in
this country is estimated at ESQ., 900 .
day. This is at the rate of one per day
20 every 160 of population. or about
5000, 900 a 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 it is pulverized by stamps
under water. the particles floating off
with the water through a series of
tanks. It comes to the factory in bar
sels, in the form of dust. The powder
is lusterless and of dingy color. 1t
is finer and softer than any flour. and
Fan be taken up in the hand just as
water can, but is hardly retained more
easily than water is. If one attempts
20 take pinch of it between the fore
finger and thumb it is as evasive as
quicksilver, and the only sensation left
S that the flesh is smoother than be-
lore.
The first process in manufacturing is
to separate the graphite dust further,
according to tineness. It's mixed with
sufficient water to run very freely. and
is then turned into a hopper. from
which the water runs slowly through
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 I'M
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water is withdrawn by removing sue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, a 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-
post from the last tub only is used,
but for ordinary and cheap grades that
from the two before the last will an
ever.
The graphite is now ready for the
clay. This is peculiar pipe clay,
from Germany. Alter being subjected
10 the floating process, the finest is
mixed with the graphite, in proper
tions varying according to the degree
ct hardness required. The more clay
used the harder the pencil For me-
dunn 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, for
the finest pencils as many rs 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
small vertical iron cylinder, having a
solid plunger or piston driven by a
screw. A plate is inserted in the bot
tom, having an opening of the shape
and size of the lead desired, and the
graphite is slowly forced through the
hole. exactly as water is forced through
syringe. coiling itself round and
round like coil of wire on a board
Set beneath the press. The COLI is taken
up at intervals, ''rove" off straight by
the hands into lengths sufficient for
three leads, which are Strengthened
out laid in order on a board, and
pressed hat by putting 3 cover over
them. They are finally hardened by
placing them in a crucible and baking
m kiln. The handling must be done
as the leads begin dry
ms Immediately and become brittle as
they dry; but on first issuing from the
pres they are SO plastic that knots
may be tied loosely in them.
The leads are now ready for their
wOode n case. For the cheapest pencil
pine is used, for the common grades an
ordinary quality of red cedar. At the
the cedar is cut into
blocks about seven inches long,
and these re sawed into strips about |
three and half inches widc
md three-s ixteenths of an inch
thick. The pencil consists of two parts !
glued together. with the lead be-
'wesn. Each strip is wide enough to
make the halves of six pencils The