Iron County register. [volume] (Ironton, Iron County, Mo.) 1867-1965, 1883-05-10

stones is about as follows: The LAYER
or ledge of rock being uncovered. chan
nels are cut at each end of the slab to
be removed, and then row of holes is
drilled on the line where the fracture is
to be made. Steel wages are driven into
these holes, driving them consecutively
little at atime. keeping all on strain,
until the mass cleaves from the ledge
forming large parallelopiped. This
block is similarly divided into squares,
and these, if too thick, are split or cleft
In the plane of the stratum to the thick
ness required. The square stone is now
chlpped into an octagonal shape, when
1t Is ready to have the eye made This
is done by the pick-hammer. 1t is then
mounted on mandrel driven at the
rate of 12J revolutions minute. The
turning tools are five feet long, one and
half inches wide, and iive-eighths of
an inch thick, tapered to point by the
blacksmith, and afterward hammered
to hooked point by the workmen, who
turn from one hundred to two hundred
a day. according to size. An exhaust
fan withdraws the stone dust, and a
conductor leads it to the outside of the
building. The stones are placed in a
row. an iron rod and wooden axis
through them, a wooden head at each
end being damned against the stone by
nuts. Stats nailed to the wooden heads
and hoops over the. Stats complete the
package. The works at .Berea, o., are
the largest in the United States.
The large .grindstones employed in
grinding gun BARRELS are eight feet in
diameter, and are used until they are
reduced to a diameter of about two feet,
when they are rejected. They are
placed in a case with holes for the in
PRODUCTION of the barrel, which is tenn
porarily slipped upon rod, a crank at
one end of the latter enabling the bar
rel to be turned while the stone is rap
idly revolved. The case keeps the
water from splashing upon the work
men, and may afford some protection
against pieces when the stone bursts, as
it sometimes will, owing to the rapid
rate at which it is driven. The danger,
of fracture can not be entirely obviated,
but may be much lessened by clamping
the stone on its axis by disks instead of
wedges inserted between the sides Of the
eve and the square arbOr on which it is
suspended. 1t would seem possible to
avoid the eye altogether, and depend
upon check-pieces with studs or pro-
jections which penetrate. into depres-
sions in the sides of the stones. The
stones are so heavy that their fracture
when in rapid motion is apt to do great
damage to life, limb and property
Artificial stones are largely employed,
especially in dry grinding and polish
ing.
The corundum stone used by the Hin
docs and Chinese is composed of corun-
dun powdered, two parts; lac resin,
one part. The two are intimately mixed
in an earthen vessel, kneaded, tlattened,
shaped and polished. A hole for the
axis is made by heated copper rod.
The grain is more or less fine, accord
ing to the grade of the powdered
corundum. The whole is mounted
horizontally, and revolved by a bow
in the right hand of the workman. while
the left applies the work to the stone.
The following recipe may also be EN-
ployed: Sand of the required fineness,
three or four parts; shellac, one part;
melted, Incorporated and nodded under
pressure.
|. Ransome' s. artificial stone, sand ag
glomerated by silicate of lime, has been
| used for grindstones with excellent
effect. In a, test trial between Ran
someS artificial TrlndStones and some.
Newcastle grit to ascertain which had
the greatest abrasive effect. it was found
that the Ransome stone ground away
quarter of an ounce from Il steel bar
three-quarter inch diameter in sixteen
minutes, while a Newcastle stone l(nat-
ural grit driven at twenty per cent.
greater speed required eleven hours to
effect the same work.
Stones for grinding cutlery vary in
diameter from four inches to two feet.
The faces of some, as of those for grind
ing razors, are convex. Those for dry
grinding. an operation very detrimental
to health, have tiue above, through
which the small particles of stone and
metal are driven by an air blast. The
angles formed by the faces of the cut
ting fools increase in proportion to the
hardness of the material to be operated
upon. Great care should be taken,
where tools requiring an accurate edge
are to be ground, to keep the face of the
stone true. This may be effected by
hanging pairto grindstones SO that
theirfaces shall touch. Their rotation
thus causes each to wear away the inc