IMPROVEMENTS IN MACHINERY FOR GRINDING SAWS AND FLAT PLATES OF STEEL
Year: 1859

page_text: LETTERS PATENT to Mark Firth, of the Firm of Thomas Firth and Sons,
of Sheffield, in the County of York, Steel Manufacturers and Merchants,
for the Invention of "IMPROVEMENTS IN MACHINERY FOR GRINDING SAWS
AND FLAT PLATES OF STEEL."-A communication by E. T. Jones, residing
in Montreal.
Sealed the 22nd September 1859, and dated the 26th March 1859.
PROVISIONAL SPECIFICATION left by the said Mark Firth at the Office
of the Commissioners of Patents, with his Petition, on the 26th March
1859.
I, MARK FIRTH, of the Firm of Thomas Firth and Sons, of Sheffield, in the
County of York, Steel Manufacturers and Merchants, do hereby declare the
nature of the said Invention for "IMPROVEMENTS IN MACHINERY FOR GRINDING
SAWS AND FLAT PLATES OF STEEL," (communicated to me by E. T. Jones,
residing in Montreal, to be as follows:-
I arrange beneath a grinding stone an adjustable table, supported at one
end by a short shaft forming a binge which rests on a casting or pan. To
this casting or pan are fixed set screws for regulating the table, that it may
grind the saws thinner on the back if required. The other end of the table
rests on a screw attached to a wheel, by means of which the table can bo
raised to the face of the grinding stone or withdrawn from it at pleasure. On
top of said table I place a carriage on which the saw to be ground is placed,
and which is made to traverse backward and forward in a direction transverse
to the axis of the stone or nearly so. To prevent the saw from coming off the
carriage, while in the process of grinding, I affix a plate of metal at one end of
the carriage of nearly the same thickness as the saw to be ground, one end
of the saw coming against the said plate prevents it from coming off the

page_text: carriage while grinding. I also place a cover over the saw to provent it from
springing off the carriage. The table and carriage rest on a wooden frame, to
which are attached two standards for supporting the brackets in which the
shaft supporting the grinding stone revolves.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Mark Firth in the Great Seal Patent Office on the 26th
September 1859.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, MARK
FIRTH, of the Firm of Thomas Firth and Sons, of Sheffield, in the County of
York, Steel Manufacturers and Merchants, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing dato the Twenty-sixth day of March, in the year of our
Lord One thousand eight hundred and fifty-nine, in the twenty-second
year of Her reign, did, for Herself, Her heirs and successors, give and grant
unto me, the said Mark Firth, Her special licence that I, the said Mark
Firth, my executors, administrators, and assigns, or such others as I, the
said Mark Firth, my executors, administrators, and assigns, should at any
time agree with, and no others, from time to time and at all times thereafter
during the term therein expressed, should and lawfully might make, use,
excrcise, and vend, within the United Kingdom of Great Britain and Ireland,
the Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN
MACHINERY FOR GRINDING SAWS AND FLAT PLATES OF STEEL," (communicated to
me by E. T. Jones, residing in Montreal,) upon the condition (amongst others)
that I, the said Mark Firth, my executors or administrators, by an instrument
in writing under my, or their, or one of their hands and seals, should par-
ticularly describe and ascertain the nature of the said Invention, and in what
manner the same was to be performed, and cause the same to be filed in tho
Great Seal Patent Office within six calendar months next and immediately
after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Mark Firth, do hereby declare the
nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement thereof, reference being had to the Drawings hereunto annexed
(that is to say):-
I arrange beneath a grinding stone an adjustable table supported at one end
by a short shaft forming a hinge which rests on a casting or pan. To this

page_text: casting or pan are fixed set screws for regulating the table, that it may grind
the saws thinner on the back if required. The other end of the table rests on
a screw attached to a wheel by means of which the table can be raised to the
face of the grinding stone or withdrawn from it at pleasure. On top of said
table I place a carriage on which the saw to be ground is placed, and which is
made to traverse backward and forward in a direction transverse to the axis of
the stone, or nearly so. To prevent the saw from coming off the carriage while
in the process of grinding, I affix a plate of metal at one end of the carriage of
nearly the same thickness as the saw to be ground. One end of the saw coming
against the said plate prevents it from coming off the carriage while grinding.
I also place a cover over the saw to prevent it from springing off the carriage.
The table and carriage rest on a wooden frame, to which are attached two
standards for supporting the brackets in which the shaft supporting the
grinding stone revolves.
By the arrangements just described the following advantages are derived,-
First, the use of a bed plate arranged on top of the carriage so as to be
adjusted obliquely to the horizon or circumference of the lap or grindstone
(when it is desired to grind saw blades which are of taper form in their
transverse section) is avoided, and thus the inconveniences and inaccuracies
experienced from the bed plate springing or changing its shape is overcome.
Second, the carriage ways and carriage and all the attachments thereof can
be reciprocated laterally at intervals in the path of a circle so as to avoid
irregular wearing of the circumference of the stone, and so as to have the
impressions or lines made by the lap or grindstone run at right angles to the
ends of the blade instead of diagonally thereto, and thus produce a better finish
and avoid impairing the strength of the saw blade by grinding it across its grain.
It is very essential to have the parts arranged to turn on a centre and to be
moved by a travelling truck arrangement, as this allows of the whole machine
having the requisite adjustments, notwithstanding its great weight, given to it
very conveniently and readily with the application of slight power.
Third, a stop is provided for the end of the saw blade to rest against as the
longitudinally reciprocating carriage traverses, and facilities for grinding all
thicknesses of blades afforded, and the blade while being ground is held perma-
nently down to the top of the carriage in a manner to avoid the end springing
up shortly after it passes beyond the axis of the lap or grindstone.
Figure 1 of the accompanying Drawings is a plan of a saw-grinding machine
constructed according to this Invention; Figure 2 is an end view; and
Figure 3 is a longitudinal vertical section of the same. The same letters of
reference indicate like parts in all the Figures.

page_text: A is the frame of the apparatus which supports an ordinary lap or grindstone
B, which is made fast on a horizontal shaft C, and revolved in the path of a
vertical circle with the same; D, D, are the carriage ways, and D¹ the carriage
arranged on top of the same. The ways are connected together laterally, and
lung at one end to a pillow block E by a pivot F, and connected at the other
end to a vertical support G by a ball and socket joint a. The pillow block E
is composed of three parts b, c, d; the pȧrt b is stationary and has the part c
connected to it by a pivot or axial pin e, which fits in between the part c and
the part d, being effected by means of a dovetail g on the part d, as shown in
Figure 2 in dotted lines. The part d is furnished with four adjusting screws
h, h, two on each side. By these screws the parts c, d, and the carriage
ways can be adjusted laterally, either right or left, to a position oblique to
the horizon or the circumference of the lap or grindstone. It is by thus adjusting
the carriage ways that the necessity of using a light bed piece on the recipro-
cating carriage for the saw to rest on is avoided, and the disadvantages arising
The
from a springing at the centre of said thin light bed piece avoided.
support G of the loose end of the carriage ways D, D, rests on a wheeled
truck II, being fastened in a screw-tapped socket formed in the centre of the
truck frame by means of a screw thread on its lower end, said screw thread in
combination with the tapped socket and windlass arms i, i, of the support
serving as a means whereby to adjust the carriage ways and carriage with all
attachments longitudinally on its pivot F to a position oblique to the horizon, so
The truck in which the
as to grind saw blades of varying thicknesses.
support E rests is arranged to travel or reciprocate on the railway I which
forms part of a circle, its motion being imparted to it by means of an endless
chain J, which passes round pulleys j, 1, and attaches by its ends to the back
and front of the truck; the endless chain passes twice round the windlass
pulley, so that it shall act with sufficient friction to cause the carriage to
inove back and forth. It is by thus having the carriage ways, &c., arranged
that the saw blades can be adjusted with the carriage ways and carriage so as
to be ground in line with its grain by the lap or grindstone, and also that
irregular wear of the stone is avoided, and likewise that great ease and con-
venience in adjusting the machine for these purposes are secured. K is a stop
on the front end of the longitudinally reciprocating carriage D¹ for the end of
the saw blade to rest against, as shown; L is a capping plate for holding
down the saw. This plate is adjustable up and down to suit varying thick-
nesses of saws by means of slotted standards k, k, transverse bars 7, 1, and set
screws m, m, in the manner illustrated in the Drawings, or otherwise, as may
be found most convenient, as it has no chance to move longitudinally or to

page_text: spring upward. The reciprocating carriage is propelled by means of a screw
shaft L' and nut M as usual, said screw shaft being set in motion by means of
bevil wheels N, N', N', the wheel N being on the end of the screw shaft, and
those N', N', being on the pulley shaft O, which carries pulleys P, P, P, from
which a belt passes to an ordinary counter or main shaft not shown. The lap
or grindstone is set in motion by a belt passing from the main driving shaft
to a pulley Q on the shaft of the lap or grindstone.
And having now described the nature of the said Invention, and in what
manner the same is to be performed, I declare that I claim as the improve-
ments in machinery for grinding saws and flat plates of steel,―
First, the arrangement of the longitudinal carriage ways on supports, so that
they with the carriage and all attachments may be inclined laterally and caused
to stand obliquely to the horizon or the circumference of the lap or grinding
stone for the purposes set forth.
Second, arranging one of the supports of the machine on a pivot, and tho
other on a truck which reciprocates on a circular railway, so that the carriage
ways and carriage, with all attachments thereof, may be adjusted in the path
of a circle, so as to stand oblique to the shaft of the lap or grindstone
substantially as and for the purposes set forth.
Third, providing the longitudinal reciprocating carriage with a stationary
stop and a capping or holding down plate, which is adjustable up and down,
but stationary longitudinally, substantially as and for the purposes set forth.
In witness whereof, I, the said Mark Firth, have hereunto set my hand
and seal, this Twenty-fourth day of September, One thousand eight
hundred and fifty-nine
MARK FIRTH. (LS.)
Signed, scaled, and delivered by the
above-named Mark Firth, in the
presence of
WILLIAM LITTLEWOOD,
Clerk to Messrs. Thomas Firth & Sons,
Merchants, Sheffield.
JNO. W. PYE SMITH, jun'.,
Law Student, Sheffield.