|
FIRE IN THE EARTH
|
||
|
|
||
|
ness and sharpness of the saw: it is about four thousandths of an inch thick.
To
prevent the stone from bending or wrecking the disc, the latter is
firmly held by thick washers of such diameter that the annular ring
exposed is just a little wider than the section to be cut. The stone is
gripped on opposite sides by a clamp, forked in shape so that the saw
can work between its "jaws." Diamond powder, 'mixed with olive oil, is
worked into the edge of the disk by means of a steel roller. That
explains how the saw is able to pierce the diamond. A clamp is held
above the saw by an arm so that it works through the stone by the
effect of gravity, an adjustable stop preventing overrunning. When the
diamond is almost sawed—and in the case of a one-carat stone this will
be in about fourteen hours—a paper bag is placed around the saw so that
the loose piece will not drop to the floor and possibly be lost.
"Lost"
stones are rare in this cutting establishment. There used to be a time
when they might fly out the window. Now the windows are closed or well
screened, the rooms being air cooled for comfort. Once in a while a
diamond flies off a polishing wheel, and then there is a frantic
sweeping of floors, a searching of every comer of the room until it is
found.
After
the sawing, the diamond goes to another room to be cut and after that
to be polished. The lay reader may hear a lot of other technical terms
to describe these operations but these are the terms of long American
usage. The first operation has also been called bruting, grinding,
roughing, and rounding. They all mean the same thing. The verbal
substantive bruting was introduced from the French as the' equivalent
of brutage or roughing, closely allied to the word brute in its now
rare meaning of rough or unpolished.
(88)
|
||
|
|
||