AN IMPROVED SURFACE-TESTING APPARATUS FOR USE IN DRESSING MILL- STONES
Year: 1879

page_text: LETTERS PATENT to William Robert Lake, of the Firm of Haseltine, Lake,
& Co., Patent Agents, Southampton Buildings, London, for the Invention of
"
AN IMPROVED SURFACE-TESTING APPARATUS FOR USE IN DRESSING MILL-
STONES." A communication from abroad by John Thompson, of Crestline, Ohio,
United States of America.
Sealed the 5th September 1879, and dated the 24th March 1879.
PROVISIONAL SPECIFICATION left by the said William Robert Lake at the
Office of the Commissioners of Patents on the 24th March 1879.
WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, & Co., Patent Agents,
Southampton Buildings, London. "AN IMPROVED SURFACE-TESTING APPARATUS
FOR USE IN DRESSING MILL-STONES." [A communication from abroad by John
Thompson, of Crestline, Ohio, United States of America.]
This Invention relates to the dressing of the faces of millstones, and is designed
to provide a substitute for the "red staff" or testing device heretofore used.
In carrying the said Invention into practice I provide a circular or otherwise
shaped metallic plate faced off in a lathe to a perfect surface, such as is desired on
the face of the stone to be dressed. The plate is made substantially of the same
diameter as the stone, and when coated with paint and brought in contact with the
face of the stone it will indicate the parts of the stone to be picked or dressed off at
an operation.
The said plate may be made annular, so as to cover only the skirt of the stone,
which has to be brought to a true surface; or the plate may be constructed with
the inner portion crowning, so as to adapt it for use on the bosom of the stone, as
is sometimes desired by millers. The said plate may be made solid, or portions of the
upper surface may be cut away to lighten the apparatus or "staff," and economize
material.
In the manufacture of these plates great strength and rigidity are necessary to
prevent them from warping or sagging from a true surface. To accomplish this I
usually construct the plate with a vertical flange around its periphery or circum-
ference. From this flange are ribs extending towards the centre, and attached to
a hub or ring. The said ribs may be made of any desired shape or configuration to
Posice Sd71

page_text: secure the greatest strength and rigidity; their lower edges may be straight or on
parallel planes with the face of the plate, or they may be arched or rounded from
the inner edge of the plate to the upper edge of the said hub or ring.
'
It is evident that with this tester or "red staff" brought to a perfect surface on
a lathe, any dresser can secure a perfect surface on the stone, however unskilful he
may be with the ordinary staff. It is also evident that after the skirt of the stone
has been brought to a proper surface the skirt may be used as a guide for dressing
the bosom of the stone with a staff in the usual manner.
It is also evident that the said Invention may be used for producing a true surface
on a wooden "red staff," whether straight or circular, with which afterwards to dress
the faces of millstones.
It is also evident that the said plate may be varied in shape without departing
from the principle of my Invention; a square, triangular, or other shape might be
desired, and therefore I do not limit myself to any particular shape for the plate.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Robert Lake in the Great Seal Patent Office on the 23rd
September 1879.
WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, & Co., Patent Agents,
Southampton Buildings, London. AN IMPROVED SURFACE-TESTING APPARATUS
"
FOR USE IN DRESSING MILLSTONES." A communication from abroad by John
Thompson, of Crestline, Ohio, United States of America.
This Invention relates to the dressing of the faces of millstones, and is designed
to furnish a substitute for the "red staff" or testing device heretofore used. The
said Invention comprises a circular or other shaped inetal plate faced off in a lathe
to a true surface, such as is desired on the face of the stone to be dressed. The plate
is made substantially of the same diameter as the stone, and when coated with paint
and brought in contact with the face of the stone it will indicate the parts of the
stone to be picked or dressed off at an operation.
The accompanying Drawing illustrates the manner of carrying my Invention into
practice.
Figure 1 is a perspective view of the said apparatus.
Figure 2 is a section through the line y-y, Figure 1.
Figures 3 and 4 shew modifications of the said apparatus.
A represents a circular plate of metal nearly of the same diameter as the stone to
be faced; this said plate may be made annular, as shewn in Figures 2 and 3, so as
to cover only the skirt of the stone, which has to be brought to a true surface; or
the plate may be constructed with the inner portion convex or "crowning," as
shewn in Figure 4, so as to adapt it for use on the bosom of the stone, as is some-
times desired by millers. The plate A may be made solid, or portions of the upper
surface may be cut away, as shewn in Figure 1, to lighten the apparatus and econo-
mize material.
In the manufacture of these plates great strength and rigidity are necessary to
prevent their from warping or sagging from a true surface. To accomplish this
result I usully construct the plates with a vertical flange B around its periphery or
circumference. From this flange ribs C extend towards the centre, and unite with
the hub or ring D. The said ribs may be made of any desired shape or configura-
tion to secure the greatest strength and rigidity. I have shewn them with their.
lower edges straight or parallel with the face of the plate, but they may be arched
or rounded from the inner edge of the plate to the upper edge of the hub or
ring D.
It is obvious that with this tester or "red staff" brought to a perfect surface in
a lathe, any dresser can secure a perfect surface on the stone, however unskilful he
may be with the ordinary staff. It is also obvious that after the skirt of the stone
has been brought to a proper surface the skirt may be used as a guide for dressing
the bosom of the stone with a staff in the usual inanner.
It is further obvious that the said Invention may be used for producing a true
surface on a wooden "red staff," whether straight or circular, with which afterwards
to dress the faces of millstones; and it is evident that the plate A may be varied in
shape without departing from the principle of the said Invention; a square, trian-
gular, or other shape might be desired, and therefore I do not limit myself to any
particular shape for the plate.
Having thus fully described the said Invention as communicated to me by my
foreign correspondent, and the manner of performing the same, I wish it understood
that I claim,
The apparatus forming a face-tester for millstones, and consisting of a metal

page_text: plate provided with the ribs, the flange, and the hub or ring, as described and as
shewn in Figures 1 and 2 of the Drawing, or any mere modification thereof, as
above set forth.
In witness whereof, I, the said William Robert Lake, have hereunto set my
hand and seal, this Twenty third day of September, in the year of our Lord
One thousand eight hundred and seventy nine.
WM. ROBT. LAKE. (L.S.)