Pittsburg dispatch. [volume] (Pittsburg [Pa.]) 1880-1923, 1892-05-15

class of labor employed in the use of these
wheels Is very expensive, running up to u
day. The saving, therefore, will be three.
fold, In labor, time and efficiency. In all
probability the finer grades of carborundum
will be used with cloth and paper, as emery
powder now is. A short time ago some car.
| borundum was submitted to a plate glass
manufacturer. Testing the material in his
Office he decided it was too soft, but he
| afterward found when trying it in the
factory that it was too hard, and for this
| reason:
Too Hard on Plate Glass.
The finishing process of plate glass is
started with sand, and then coarse grade
of emery powder is used. In the course OF
pressure and abrasion the emery particles
break down, and become so reduced as to
leave the glass in high state of finish. The
carborundum would not break down, but
left the glass finished in o degree represent
ed only by its original fneness, and the
conservative glass fnlsher declined to
countenance such sweeping innovation,
even though promised powder of any
degree of fineness he wished.
In the grinding of valves and cocks the
present practice of using a coarse emery
powder to begin with causes grooves to be
left in the metal, and these have to be taken
out by a second process. The actual cost of
the emery is a small part of the total ex-
pense of the process. A man receiving $3
day will scarcely use pound of emery in
two weeks. With carborundum this pro-
cess can be carried out at the first intention.
and with an efficiency of 80 per cent in ex-
cess Of the old process Beyond this. 1t en-
ables the manufacturer to turn out class of
work, the cost of producing which by the
ordinary emery method would be prohibi-
tive.
Equal the Dentists Diamond Wheels.
One of the most effective uses of car
borundum will be in the construction of
points for dental engines for the excavation
and grinding down of teeth. These points
are already made in various sizes, and are
commended by dentists with enthusiasm,
and declared to be, when properly bound,
equal in every respect to diamond wheels.
The diamond wheel is disc of copper
charged with diamond powder, and when
used 1t has to be kept continually wet.
Another disadvantage is that as the ineness
of polish produced on tooth increases, the
effectiveness of the abrading surface de-
creases, and the expenditure of additional
time and labor becomes necessary.
The difference between the ordinary and
the carborundnm point was shown recently
in q dentists parlor In New York, where
the dentist quietly substituted the latter for
the former. The patient instantly noticed
the change, and described it as the difference
between "clean-cutting and jagged-sawing.
Most people have had their share of bad
quarter-ot-an-hours with the dentist, and
have vivid recollection of the sickening
of the cutting wheel. 1t is comfort
ing to know that this form of martyrdom can
now be banished. AS showing to what ex-
tent small units grow into big Industries, it
may be stated here that there are $4,000
dentists in this country, each of whom uses
on an average $40 worth of wheels year,
an expenditure of $3.50, 900.
Other Cses of the Wonderful Material.
For the cutting Of rock crystals for
lenses tests have shown carborundum to be
effective, and for this purpose it
is likely to completely supersede emery,
which is now used. A singular character
istic of carborundum is that its abrasive
power is increased in proportion to the
hardness of the material operated upon.
For instance, while in lead plate cutting it |
would show no higher in efficiency than |
emery, in treating chilled iron or steel its |
would be markedly manifest.
OF course, the main interest of carborun- |
dunn to the scientist will be centered on its |
newly-found adaptability to the purposes of |
3 wonderful discovery, and more especially |
will this be the case when crystals large |
enough to form an entire button are pro- |
1uced, which is easily conceivable. But !
enough has been said to justify its claim to |
be considered one of the most remarkable |
products of recent years, and |
one which will effect revolution in large |
number Of industrial fields.
GEORGE HE'LL GUY.