The Abbeville press and banner. [volume] (Abbeville, S.C.) 1869-1924, 1886-08-18
LEAD PENCILS.
THE INTERESTING PROCESS OF
THEIR MANUFACTURE.
Graphite and its Peculiarities-Mix-
ing the Clay and Forcing the Coll
Filling the Wooden Case
Separating and Shaping.

every loU VI PopuloIIon, "a eUous -
900, 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. Hereitis
pulverized by stamps uuder water, the
particles floating off with the water
through a series of tanks. 1t comes to
the factory in barrels, in the form OF
dust. The powder is lusterless and of
O dingy color. 1t is finer and softer than
any flour, and can be taken up in the
hand just rs water can, but is hardly re-
tanned more easily than water Is. If one
attempts to take pinch of it between
the forefrger and thumb it is as evasive
as quicksilver, and the only sensation
left is that the flesh is smoother than
before.
The first process in manufacturing is to
separate the graphite dust further, &C
cording to fncness. 1t is mixed with
sufficient water to run very freely, and
is then turned into hopper, from which
the water runs slowly through series of
tubs. The coarsest and heaviest rartl-
c!es settle to the bottom of the first tub,
the next coarscst and heaviest in the
next, and so on, tie movement of the
water being made very gentle. On reach
ing the last tub, the powder, being twice
as heavy as water and sinking in it if
undisturEed, has so far settled that the
water discharged at the top is nearly
clear. After the flow is stopped anl the
powder allowed to settle, the clear water
| is Withdrawn by removing successfully,
beginning with the upper one, a number
| OF plugs inserted in holes in the side OF
each tub, care being used not to agitate
the contents so as to disturb the deposited
dust. This being done properly, the de-
post is removed through the gates at
the bottom of each tub. The separation
| is thus performed, by this ingenious pro-
cess of '"Aoating," more perfectly than
it could be by any direct handling, dry
treatment being wholly impracticable.
For the finest pencils the deposit from
the last tub only is used, but for ordi-
nary and cheap grades that from the two
before the last will answer.
The graphite is now ready for the clay.
This is a peculiar pipe clay from Ger
many. After being subjected to tho
floating process the finest is mixed with
the graphite, in proportions varying ac-
cording to the degree of hardness re-
quired. The more clay used the harder
the pencil. For medium grades the
proportion is about seven parts clay to
ten graphite by weight. The graphite
and clay are mixed together with water,
to the consistency of thick cream, and
the mixture is fed to the grinding mills,
which consist of two fiat 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 as twenty-four
tines, thus securing the most pcrfe ct
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: ONES thick dough.
It then goes to the forming press. This
is simply small vertical iron cylinder,
having solid plunger or piston driven
by a screw. A plate is inserted in the
bottom having an opening of the shape
and 81 of the lead desired, and the
graphite is slowly forced through the
hoe, exactly as water is forced from a
syringe, coiling itself round and round
| like coil of wire on board set be-
Meath the press. The coil 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 board and pressed fiat by put
ting cover over them. They are finally
hardened by placing them in crucib!e
and baking in a kiln. The handling
must be done expeditiously, as the leads
be sin drying Immediately and bcc,me
brittle as they dry; but en- first issuing
from the press they are so plastic that
knots may be tied loo:ely in them.
The leads are now ready for their
wooden case. For the cheapest pencil
pine is used. for the common grades an
ordinary quality of cedar. At the saw
mills the cedar is cut into blocks, about
seven il ches long, and these are sawed
into strips about three and half inches
wide and three-sixteenths of an inch
thick. The pencil consists of two parts
glued together, with the lead between.
Each strip is wide enough to make the
halves of six pencils. The pencils ore
made six at a time, and imperfect strips
are put together so as to make full
strip out Of the parts. When tn; sc
boards (which are now ready for shaping)
reach the factory they are first past in q
continuous line, under cutter which
cuts six little grooves, round or siuarc,
for the leads, and smooths the faces by
the same ST. oke. The lead in the foreign
pencil lies wholly in one-half of the
wood, the other slip being put on as a
cover as nearly everybody has found oc-
casion to know by the covers coming
off and leaving ali unpleasantly fiat
surface; but the American meth cd
has the glue equally in each strip. Ac-
cordingly the two strips are glued alike.
Filling the leads is done by girls, sit
ting at brass covered tables The first
takes q grooved slip with her left hand
and q bunch of leads in her right.
Spreading these out in her fingers like
the sticks OF fan, she deXterously lays
them in the grooves and passes the
filed slip to the girl at the left, who puts
over it another slip which has just re-
ceived coating of hot glue from brush
welded by third. Any two slips fit
together and the united pairs are laid in
row and pressed together in an iron
frame by screw, and the row Of slips Is
left to dry. The rough ends Of the slips
and the projecting parts are next grouId
smooth against a wheel covered with
eond manor ond arn ihpn rna3v for the