Shepherdstown register. [volume] (Shepherdstown, Va. [W. Va.]) 1849-1955, 1890-08-01
Diamond Cutting.

Diamond Cutting.
After the preliminary steps OF
weighing and recording the diamond
a rough drawing is sent to the cutter
He carefully examines the stone to de-
termine the grain and best method of
procedure, taking every advantage
of the stone to produce as much ma
terial as possible in a fine brilliant
When he finds the grain he looks for
the points of the stone. In some
stones there are two points, in others
three, and never more than four
Now, knowing the grain and the
points, that determines him in plac-
ing the table, or upper face of the
stone. The grain must always run IN
to the table to facilitate the polish
ing of the facets. The purpose of the
table is to admit light and to act as
mirror in rejecting light in the facets
of the pavilion (the back of the stone
below the girdle), and which light is
again reflected as many times as there
are facets in the crown or top OF the
stone above the girdle. Naturally
the facets determine the brilliancy OF
the stone. The cutting and polishing
must always be done against the
grain of the stone or there is danger
of chipping and so running a valuable
brilliant.
The shape determined, the cutter
puts the stone into cement OF resin
and sandstone on the end of stick
shaped very much like a miniature
wooden pin used in bowling. The
stick has the same fat body,
lust large enough for the hand TO
comfortably grasp, with a narrow
neck and branching out into head
about one-half the size of the body.
On this head goes the cement and the
stone. and when the cement hardens
it holds the diamond absolutely sta
tionarv. Two sticks, each with dia-
mond, are used, as the cutting is done
by rubbing one stone against the
other. To help him in cutting and
save the diamond dust, which is after
ward used in polishing the cutter has
an iron box eight inches long, four
inches high at the back, two inches in
height at the front and three inches
wide.
The slant to the box gives the cut
Ger opportunity to move the stick IN
anv direction In order that his
hands may be steady and exert all
their force keeping the stones together
two brass uprights about one inch
high are inserted in the slanting edge
of the box, about three inches from
the front. The top surface OF the box
is divided into two compartments -
one at the back, about three inches
wide by one and a-half inches long,
with n sliding top to hold the dla-
monds to be cut, the other five
inches long and the width of the box,
with a movable fine sieve about half
down to catch the dust coming from
rubbing the two stones together.
This dust, after going through fine
sieve, is received in a small drawer
which comes out through the front Of
the box. The cutting is the most i'm
portant and hardest part Of the prep
aration Of the stone. From the con-
slant rubbing the fingers become dis
figured and knotted, and to save them
in the heavy blocking of a stone
small machine has been invented.
| Only two of these machines are in use.
The machine works on the same prin-
ciple Of rubbing two stones together
as the sticks, but cannot do such fine
work as is done by hand.
The polisher takes charge of the
! stone after it has passed through the
hands of the cutter, and judges his
work from the condition of the stone
when received. To polish the stone
/ Win 0lec0dDlcdl eAdClHees- ds has ~
be done TO get the best effect, the OPP
orator has a wheel-or ''lapp," as it is
technically called-made Of an alloy
OF iron and lead or copper. This lapp
makes ., 500 revolutions minute, and
| has to run with the least possible
friction and be perfectly balanced.
In order to get the least friction
either end of the spindle of the lapp
rests on small piece Of lamp wick
saturated with lubricating oil. The
polisher has little cup-shaped piece
of lead. with a copper rod shank
called ''dupp"-that he fills with a
mixture of lead and pewter, in which
he puts the diamond. The shank Of
the dupp is then put in the end Of the
clamp.
This clamp insures the diamond be-
ing held in steady position, and by
weighing it any amount of pressure
can be brough to bear on the dia-
mond. On this lapp is used the dia-