Watertown republican. [volume] (Watertown, Wis.) 1860-1906, 1883-04-25
GRENDSTONES.
The Different Varieties and Where They Conn
Erorn-Ar4;Gn;aI

are made from the more compact sand
stones, varying In texture and compact
ness according to the work required.
Those of England are highly esteemed
Different localities of that country afford
such as are required for every purpose.
Among these the Newcastle stones,
from the coal measures of Northumber-
land and the adjacent counties, have
-eminence In England for general
purposes; others are employed for grind
ing, while many varieties are used as
plane surfaces for whetstones. Other
qualities are used for homes. A Ger
man variety is famous for this purpose.
The very finest qualities, composed of
an almost impalpable agglutinated
power, are used as oil stones. Such are
the g Water of Ayr" and "blue stones,
and the Turkey oil stone. The old
royal exchange of London was paved
with this stone, and when it was burned,
about 1884, the pavement yielded a
handsome amount toward the re-erection.
The Nova Scotia and Berea, O., grind
stones are largely employed in this
country; these may be obtained of very
large size and uniform quality. The
Washita, Ark, stone is of the very finest
quality, being sharp and clean, and is
made into a great variety of forms
grindstones, whetstones. homes, and
slips of various sizes and forms.
In dressing rough grindstones the
process of hacking is employed. Hacking
consists III notchlng the projecting parts
with short handled hammer resembling
an adj. Laps used In polishing stones,
etc., are Jared by holding an old knife
against their edges, so as to v1brate or
chatter, making a slight indentation at
each jump; these serve to retain the
fnely-powdered emery or rOttenstone
mixed with adhesive material, with which
the lap is covered. For clearing the sur
face of stones, In which particles of iron
or steel have become Embedded, square
bar of one-half to one-Quarter inch iron
is held and wabbled against the edge
while in motion. This is called stray
Cling or raging. Turning or rowing is
effected by reversing the motion of the
stone end holding a hooked fat tool
against its edge, which is afterward fur
ther smoothed by the rowing plate The
series of operations in making grind
stones is about as follows: The Layer or
ledge of rock being uncovered, channels
are cut at each end of the slab to be re-
moved, and then row of holes is drilled
on the line where the fracture is to be
made. Steel wedges are driven
into these holes, driving them con-
secutively a little at a time, keep
ing all On strain until the mass
cleaves from the ledge forming a 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 thickness required.
The quare stone IS now Clipped into an
octagonal shape, when it is ready to
have the eye made. This is done by the
pick hammer 1t is then mounted on
mandrel driven at tberate of 125 revolu-
tons O minute. Tue turning tools are
five feet long one and half inches wide,
and five eighths Of an inch thick, taper
ed to a point by the blacksmith, and af-
terward hammered to hooked point by
the Workmen, who turn from one hun
dred 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 row, an iron rod and
wooden axis through them, a wooden
head at each end beng damned against
the stone by nuts. Stats nailed to the
wooden heads and hoops over the stats
complete the package. The works at
Berea, Ohio, 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 re-
duced to a die meter of abont two feet
when they are rejected. They are placed
in a case with holes for the introduction
of the barrel, which is temporarily
slipped upon rod, crank at one end
of the latter enabling the barrel to be
turned while the stone is rapidly re-
volVed. The case keeps the water from
splashing upon the workmen, and may
afford some protection against pieces
when the stone bursts, as it sometimes
Will, wing 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 in
serted between the sides of the eve and
the square arbor on which it is suspend
ed, 1t would seem possible to avoid the
eye altogether and depend upon check
pieces with studs or projections which
penetrate into depressions 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 large
" employed, especially in dry grinding
and polishing.
The corundum stone used by the Hin
docs and Chinese is composed of corun-
dunn powdered, two parts; lac resin, one
part. The two are Intimately mixed in
an earthen vessel, kneaded, fattened,
shaped and polished A hole for the
axis is made by heated copper rod.
The grain is more or less fine according
to the grade OF the powdered corundum.
The whole is mounted horizontally and