Improvements in the Manufacture of Circular Saw-plates and Apparatus therefor.
Year: 1888

page_text: Improvements in the Manufacture of Circular Saw-plates and
Apparatus therefor.
I, WILLIAM HENRY SINGER, residing at the City and County of Alleghany, in
the State of Pennsylvania, one of the United States of America, Steel Manu-
facturer, do hereby declare the nature of this invention and in what manner
the same is to be performed, to be particularly described and ascertained in and by
the following statement :-
My invention relates to the manufacture of circular saw plates, and to the apparatus
employed in connection therewith, these plates being formed from cast steel, and
especially in the large sizes thereof costing a large amount to make, and in the finished
article being very expensive.
The object of my invention is to form a circular saw plate entirely free from any
such imperfections as will form splits or seams in the finished saw, and so over-
come the most serious difficulty in connection with the manufacture and use of these
articles.
The method heretofore practiced of making these plates has been to cast steel of
proper carbon in the ordinary ingot mold, it being found that the ingot so cast always
contains a pipe cavity caused by the settling of the steel in cooling, as well as other
cavities or honeycomb, and after removing the portion supposed to contain the "pipe
cavity," to reduce the ingot to plate. This ingot was rolled down in all directions so
as to produce a plate as nearly as possible of the proper gauge and of even thickness
throughout, and after the plate had been so rolled it was cut by suitable tools to the
desired circular forin.
In the large sizes of saws as those of from four to six feet diameter, the circum-
ference of the plate thus obtained would be from 12 to 18 feet, and the custom has
been to examine carefully the edge of the saw around its entire circumference, by
means of a microscope in many cases, in order to discover whether there are any
seams or imperfections in the edge of the plate, so that such plates may be approved
oi condemned for saw making purposes.
Where the plate was, so far as this examination showed free from seams and

page_text: cracks, the plate was shipped to the saw manufacturer; the plate was then taken by
the saw manufacturer, the teeth cut therein, the plate properly tempered and then
made perfectly straight and true, this operation requiring a very careful hand
hammering by men long skilled in the art. The saw plate thus produced was then
ground by suitable grind-stones and thereby brought to a perfect gauge, and subse-
quent to the grinding was properly polished, the saw being then ready for the
finishing operation of spreading or swaging the teeth. These operations, especially
in large sized saws are expensive and raise the expense of the saw in many cases to
from $175 to $200, and all these operations would in many cases, be performed
without discovering any imperfections in the plate, even though careful search
therefor was made but though the plate had so far been found to be perfect in
weld, the swaging of the teeth would in many cases develop seams or splits in the
metal. the metal being spread under the swaging operation and it frequently
occurring that as the point of the tooth was spread the metal would part in the
tooth, and in some cases flake off, so rendering the plate useless, or at least,
rendering it necessary to repeat the entire manufacture of the plate, cutting it down
to smaller diameter, and in many cases, as the seams or splits would extend for a
considerable distance into the metal, the same imperfections would be developed in
the smaller saw. It would also often occur that as these seams were caused by
pin-holes or blow-holes in the body of the ingot, which could not be closed and
rewelded after the metal was set, and though the saw when finished and its teeth
swaged might seem perfect, yet after it had been in use for a considerable period the
gumming of the saw would cut into the seam or split in the metal and the saw thus
be rendered useless, so that the saw maker would be compelled to replace it with a
perfect one. These difficulties in the manufacture of circular saw plates have been found
for years, and have been the source of large losses to the steel maker and the saw
manufacturer, as well as the user of the finished saw, and it has become evident
that by the overcoming of such difficulties in the manufacture of these articles a great
advance in the art would be obtained. The manufacture of these plates has also here-
tofore required a considerable waste of metal, as the plates were rolled from angular
ingots, and in rolling the plates to the exact gauge it was necessary to roll them
in all directions, so that there was a considerable waste of metal in the plates,
especially for the larger sizes of saws.
After careful consideration of the subject, together with experimenting at large
expense in connection therewith, I have been enabled to produce a saw plate which
is entirely free from these seams or splits, and in which the metal is solid and
homogeneous, and have therefore overcome the principal difficulty in the manufacture
of practically perfect circular saw plates. I have also in connection with my
improved method of forming those plates been enabled to save a large portion of
metal in the rolling of the plate, reducing the loss by scrap in the plate to a
minimum.
'
.
My invention consists, generally stated, in forming these circular saw plates free
from splits, or like imperfections, by casting the steel in a large body within an ingot
mold, and subjecting the molten steel therein to heavy and continuous pressure 'until
the metal is congealed then dividing the compressed ingot into disks of the proper
thickness to form the plates of the desired diameter and gauge, and finally heating
the disks and reducing them in thickness and enlarging the radially to form the
circular saw plates. It also consists in forming the large compressed ingot cylin-
drical in shape, and then cutting it into disks and rolling these disks in all directions
to the desired gauge, thus producing substantially circular plates of proper gauge
from which to cut the circular saw plates, it being found that in so doing 1 am
enabled to save a large percentage in waste metal. It also consists in certain
improvements in the mold in which the metal can be subjected to pressure, and the
gases expelled from the metal by the pressure, can escape through the walls of the
mold, as will be more fully hereinafter explained.
To enable others skilled in the art to practice my invention, I will describe the
same more fully, referring to the accompanying drawings, in which

page_text: pressing the ingot, illustrating the filling of the metal within the ingot mold.
Figure 2, is a like view showing the ingot under compression.
Figure 3, is a view of the cylindrical compressed ingot obtained.
Figure 4, illustrates the method of slotting or dividing this ingot into the disks or
sections of the proper weight for the formation of the plates.
Figure 5, shows the disks obtained.
Figure 6, is a view of the plate rolls employed in reducing the disks.
Figure 7, illustrates the plate rolled from the disks.
Figure 8, is a view of the finished saw plate.
Figure 9, is a sectional plan view of the casting table and mold on the line, a, a,
Figure 2.
Figure 10, is an enlarged section through two of the rings of the mold, showing
their venting arrangement; and
Figure 11, is an enlarged plan view of one of said rings.
Like letters of reference indicate like parts in each.
My invention may be employed with any suitable apparatus, that illustrated in
the drawing being found by me well adapted for the purpose. In it I employ the
This
hydraulic compressing apparatus, such as illustrated in Figures 1 and 2.
compressing apparatus consists of the bed, a, firmly supported over a pit, b, in
which is contained the two cylinders, c, d, the cylinder c, being employed to
obtain the heavy pressure necessary in compressing the ingot and the cylinder, d,
being employed to raise and lower the pressing frame during the other operations
of the apparatus. Moving in the cylinder, c, is the piston or plunger, c', which is
secured to the vertically moving pressing frame, e, formed of the lower cross-head, e',
to which the plunger, c, is secured, the standards, e², extending up therefrom and
the upper cross-head, e, carrying the pressing plunger, e, which enters the upper
end of the ingot mold. Extending down from the lower cross-head, e¹, is the piston
or plunger, d, which enters the lower or smaller cylinder, d, supported at the base
of the pit, and through which the movable frame, e, is raised and supported to
manipulate the apparatus when the compressing force is not applied, while the
plunger, c, within the cylinder, c, operates to draw down the movable frame and
impart the heavy pressure desired to the molten metal within the ingot mold, F.
This ingot mold, F, is supported on a suitable carriage, g, running on suitable
guides, a', on the stationary bed, a, and operated through the hydraulic cylinder, ',
which has therein the piston, g², the piston rod, ³ which is secured to the
carriage, g, and through which the carriage is drawn under the pressing apparatus
after the filling of the mold, or removed from the pressing apparatus after the
compressing operation, the carriage, g, resting during the operation directly above
the compressing cylinder, c. The carriage, g, has secured thereto directly under
the plunger-head, e, of the vertically moving frame, e, the base block, g, and upon this
base block is fitted the ingot mold, F, said mold as shown being formed of a series
of rings, held firmly together by bolts, f¹. To enable the rings forming the mold
to be removed more easily after the compressed ingot is cooled and to provide for the
escape of the gases expelled from the molten steel, these rings or sections are of
peculiar construction. Close to the interior wall of each ring on the top and bottom
thereof are formed the annular faces, s, while beyond said faces, s, are the bevel
or rabbit faces, s', and beyond said rabbit faces are the outer annular faces s. The
rabbit faces, s', and outer faces, s2, bear firmly upon the like faces of the adjoining
rings and thus support the rings forming the mold, but the lower rabbit face, s', is
not quite so long as the upper rabbit face, and so a slight space, v, is left between the
inner faces, s, s, of the rings, this space being however too small to permit the
entrance of sand, and simply acting as a venting groove to carry off the gases from
the sand. Formed on the rabbit faces, s¹, and outer annular faces, s³, are the venting
grooves, t, which permit the escape of the gases passing into the space between the
inner faces, a free venting of the gases from all parts of the mold being thus
obtained without permitting the escape of the sand lining. The bearing faces are

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formed near the interior wall of the mold rings and the rings are made sufficiently
thick to withstand the heavy pressure to which the metal is subjected, the tops and
bottoms of the rings outside of said faces being cut away as at, 72, to give a hold to
the crow-bars employed in loosening and raising the rings before they are lifted
off by the crane. The particular construction of these rings is fully shown in
Figures 10 and 11. The ingot mold, F, is lined with sand, in a suitable manner, this
construction of mold permitting the venting of the gases from the molten steel,
which, under the heavy pressure imparted to the molten steel is forced through
the body of sand and can escape through said vent openings between the rings of
the mold.
In forming the ingot in the most approved manner I line the ingot mold
with sheet metal as at, j. and interpose between this sheet metal lining and the inner
walls of the mold a body of sand, suitably rammed to place. The advantage of
the use of the sheet metal lining in addition to the fact that it confines the sand
within the mold and forms the interior of the mold when ready for casting,
are that it prevents the cutting away of the sand by the molten metal
when the latter is poured into the mold, and prevents the fusing of the sand
by the highly heated metal and the formation of an agglomerated layer on the
exterior of the ingot which would have to be subsequently removed, and
especially that as this sheet metal lining becomes very highly heated by the molten
metal, though when backed by the layer of sand it supports the molten metal,
yet it is punctured by the gases under the exceedingly high pressure to which the
metal is subjected and therefore, while confining the metal, in no way interferes with
the free escape of the gases from the mold. The mold cavity is formed cylindrical,
thus imparting to the compressed ingot a cylindrical shape which enables me, as
hereafter described, in rolling out the saw plate to save a large amount of waste scrap.
The cylindrical compressed ingot, h, formed as hereafter described is divided into
disks or sections, in the following manner: The ingot is supported in a suitable
lathe, k, and is centered therein in the ordinary manner, and by means of a series of
cutters, supported on the lathe at any desired position, the ingot is gradually
grooved or channeled through the same as shown in Figure 4, thus forming the
disks, 1, of the desired thickness and weight. The apparatus employed for reducing
these disks to plate metal are the ordinary plate rolls, or if desired the disk may be
first reduced under the hammer, and subsequently rolled, suitable rolls for reducing
and enlarging the disks being shown in Figure 6. Located near the compressing
apparatus is a suitable crane, carrying at end thereof a ladle, m, which ladle can be
drawn close to the casting floor, and the metal from the several crucibles poured
within the ladle, as illustrated in Figure 1.
In carrying out my improved process of forming these saw plates, the ingot mold, F,
on the carriage, g, is forced by the cylinder, ¹, to one side of the compressing
apparatus and the mold is suitably lined as before described. As soon as the molten
steel is ready to cast the ladle, m, supported on the crane, n, is brought close to the
casting floor and is gradually filled with molten metal from the crucibles, a large
body of molten steel being thus collected within the ladle. The molten steel in the
ladle is then poured into the ingot mold, a removable funnel being preferably
employed in filling the mold, to prevent injury to it or its sheet metal lining by the
molten steel. As soon as the mold is filled, a removable pressing block, r, is placed
therein to prevent injury to the pressing plunger, et, of the compressing apparatus,
this plunger, et, acting on the pressing block. The vertical moving frame, e, is then
raised by the admission of water within the hoisting cylinder, d, and the carriage, y,
carrying the ingot mold containing the ingot, h, is then drawn under the vertically
moving frame, e, by means of the hydraulic cylinder, g'. Water is then admitted to
the compressing cylinder, c, and exhausted from the cylinder, d, and the frame, e, thus
drawn down, the plunger-head, e, entering the upper end of the ingot mold and
bearing against the removable block, », placed therein. A heavy compressing force
is thus exerted upon the molten metal within the mold, through the compressing
cylinder, c, and pressing frame, e, the frame being drawn down with a force which is
gradually increased as the metal is compressed until a pressure of from six to

page_text: seven tons per square inch is brought upon the metal, and this compression is continued
until the metal within the mold is congealed, the pressure being generally continued
from three-quarters of an hour to an hour and a quarter, the gases and air contained
in the molten metal being forced outwardly by the enormous pressure through the
sheet metal lining, j, which is punctured thereby, and escaping through the body of
sand and thence between the rings of the mold and by this means all the gases or
air within the molten steel are expelled therefrom and a solid homogeneous body
entirely free from honey-comb or blow-holes are obtained, the compressed ingot being
solid and homogeneous. As soon as the metal has cooled the compressed ingot, h, is
removed from the ingot mold, this being accomplished whero a molil of sectional rings
as shown is employed, by loosening and removing the bolts, /, and removing the
several rings forming the molds, thus exposing the finished compressed ingot. As
the metal is confined while in a highly molten condition by the sheet metal lining,
the compressing ingot is delivered substantially the same diameter throughout,
and the mixing or agglomeration of the steel with the sand lining is prevented. This
ingot is then mounted in the lathe, k, and the cutting tools, 2, adjusted on said
lathe according to the size and weight of the disks to be formed, the weight of the
several disks or sections being approximately calculated according to the diameter
and thickness of the plates to be formed. The compressing ingot is then cut by this
apparatus almost through, leaving only a small portion between the several disks to
support the metal within the lathe, and after the grooving of the ingot it is withdrawn
from the lathe and the several disks broken apart, disks of proper weight for forming
the desired sizes of saw plates being thus obtained. These disks are found to be
solid and homogeneous throughout, all honey-combs, pin-holes or blow-holes which
would be found in the ordinary ingots being thus removed. The disks or blanks are
then reheated in a suitable furnace and either through plate rolls or by means of
steam hammers reduced and subsequently by means of plate rolls the disks or
sections are rolled out to the desired gauge, the disks being rolled in all directions
in order to bring them to the exact gange desired and to spread the metal evenly,
the blanks being thus enlarged radially, and forming substantially circular plate as
shown in Figure 7. After the formation of the plates they are sheared by suitable
tools forming the finished saw plates, as illustrated in Figure 8. As the disks from
which the saw plates have been formed are solid and homogeneous and the metal
thereof is firmly united and welded together, saw plates are obtained which are
without flaw, seam or split, and consequently there is no liability whatever of the
formation or opening of seams or splits in the metal by the subsequent cutting of
the saw teeth therein or the reheating and tempering of the plates, or of the
straightening or polishing of the plate; or, after the finished saw is obtained, by
the swaging of the teeth, either before the saw is shipped by the manufacturer, or
subsequently thereto, when the saw is re-sharpened or re-swaged when in use. As in
the rolling of the circular disks to finished saw plate, the plate is rolled or drawn
in all directions in order to form it of even gauge, as before referred to, the disks
draw out into a substantially circular plate, and instead of forming a large amount of
scrap metal beyond the saw plate, to be formed therefrom, there is but little scrap
formed in the cutting of the saw plate, since the saw plate is brought to substantially
circular shape during the rolling operation, a large saving being thus obtained.
By my improved process I am thus enabled to form a practically perfect saw plate
which is entirely free from hidden seams or imperfections, all liability of splitting
or opening during the subsequent operations in forming the finished saw therefrom,
or in swaging or spreading the teeth thereof being overcome, and, though a large
number of saw plates have been formed by my improved process, there have been
none formed to my knowledge in which any such seams, splits or imperfections have
been subsequently developed, either in the manufacture of the saw, or in subsequent
use, my improved process therefore giving absolute certainty of a perfect saw, where
the plate is properly handled, and the large loss, both to the saw plate manufacturer
and to the saw manufacturer being thus entirely overcome.

page_text: Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed 1 declare that what 1.
claim is :-
1. The improvement in the art of forming plates for circular saws, consisting in
casting a large body of molten steel within a mold, and subjecting it to heavy and
continuous pressure during cooling, then dividing the compressed ingot transversely
into sections or disks, and finally reducing said disks in thickness and enlarging them
radially, substantially as and for the purposes set forth.
2. The improvement in the art of forming plates for circular saws, consisting in
casting the molten steel within a cylindrical mold, and subjecting it to heavy and
continuous pressure during cooling, then dividing the cylindrical compressed ingot
into disks and finally reducing said disks and enlarging them radially to produce
a substantially circular plate, substantially as and for the purposes set forth.
3. The improvement in the art of forming blanks for the manufacture of circular
saw plates, consisting in casting a large body of molten steel within a mold, and
subjecting it to heavy and continuous pressure during cooling, and then dividing
said compressed ingot transversely into sections, substantially as and for the purposes
set forth.
4. In apparatus for compressing ingots, a mold composed of a series of rings, f
each of which has the faces », », and, 2, on the top and bottom surfaces thereof, the
said faces, s¹, being inclined or beveled and the bottom faces, s¹, being shorter than
the top faces, so forming the space, u, between the faces, s, and having the venting
grooves, t, in the faces, s', and, s2, substantially as and for the purposes set forth.
5. In apparatus for compressing ingots, the combination with a compressing
apparatus, of an ingot mold having a lining of sheet metal on its interior, and a packing
of sand or like material between the sheet metal lining and the body of the mold,
substantially as and for the purposes set. forth.
Mil 1
1000
WILLIAM HENRY SINGER.
By Jensen & Son,
7.7, Chancery Lane, London, W.C.,
Patent Agents.