IMPROVEMENTS IN SCREW-CUTTING MACHINES
Year: 1874

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn
Fields, in the County of Middlesex, Gentleman, for the Invention
of "IMPROVEMENTS IN SCREW-CUTTING MACHINES."-A communication
from abroad by Coleman Sellers, of the City and County of
Philadelphia. State of Pennsylvania. United States of America.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson
at the Office of the Commissioners of Patents, with his Petition, on
the 14th July 1874.
I, JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the
County of Middlesex, Gentleman, do hereby declare the nature of the
said Invention for "IMPROVEMENTS IN SCREW-CUTTING MACHINES," a com-
munication to me from abroad by Coleman Sellers, of the City and
County of Philadelphia, State of Pennsylvania, United States of
America, to be as follows:-

page_text: cutting or bolt threading mạchines automatically when the bolt has been
threaded a proper distance from the point.
Second. The providing means for causing a current of lubricating
fluid to pass through the revolving dies in the direction opposite to the
motion of the bolt entering the dies, so as to wash out the chips, to
lubricate the cutting edges, and to keep the dies cool.
Third. The providing means of regulating the supply of the fluid from
a pump to the parts of the machine requiring it, as in threading bolts
or in tapping nuts, and controlling or directing the force of the current
so as to insure the performance of these objects.
The first part of the Invention is applicable to that class of screw-
cutting or bolt threading machines in which revolving dies open to
liberate the bolt when cut, and consists in providing an adjustable stop
in the centre of a hollow spindle to be pressed against by the end of the
bolt which is in course of being threaded, and by suitable devices
to actuate the opening machinery and liberate the bolt at the required
time.
The Invention relates, secondly, to the same class of machines, and
consists in utilizing the levers and devices required for the stop motion
as a means of conveying fluid to the back of the hollow spindle, and
thus causing the flow of liquid from within outward for the purpose of
washing out the chips, which otherwise tend to clog up the cutting
parts.
The Invention consists, thirdly, in arranging the pump which supplies
the liquid with an overflow valve, so that with a constant amount of
delivery by the pump such quantity of the liquid as may be required
can be directed to the parts requiring lubrication.
In applying this Invention to the screw cutting machinery for which
Letters Patent were granted to Mr. William Sellers, May 3rd, 1859,
No. 1109, the apparatus is arranged in the following manner :-
In the machines as ordinarily made the dies are placed in radial grooves
in a cylindrical die box or holder, which is secured to one end of a hollow
spindle, to the opposite end of which is attached a driving spur wheel.
Surrounding the die box is what is termed a cam box, consisting of cams
of equal eccentricity bolted to an annular projecting end of a sleeve

page_text: which surrounds the hollow spindle, and having other cams of similar
eccentricity secured to a cover plate. The rotation of the sleeve to and
fro around the spindle causes the dies to be moved in a radial direction,
thus opening or closing the dies. To the sleeve is secured a spur wheel,
smaller in diameter than the spur wheel on the spindle, and the extent
of rotation of the sleeve around the spindle is limited by an adjustable
stop situate between the two spur wheels. These spur wheels are driven
by pinions carried on a shaft, the pinion which is in gear with the spindle
spur wheel being fast on the shaft, whilst the other is loose, but is
pressed towards the former pinion by means of a spring on the shaft, and
is driven by the friction of the surfaces of a leather disc interposed
between them.
The pinion which is in gear with the sleeve spur wheel may by means
of a lever and collar be drawn away from the other pinion, and made
to engage in a recess formed in one of the legs of the machine, a bevelled
collar on the pinion fitting this recess after the manner of friction
clutches. When this latter pinion is driven by the other, it tends, by
reason of the difference in diameter of the two pairs of wheels, to cause
the cam box to rotate faster than the die box to the limit allowed by the
stop, which has the effect of closing the dies, but when the motion of the
pinion is retarded by the friction on the recess in the leg it causes the
dies to open.
According to this Invention it is proposed to add to the machines as
ordinarily made a tank supported on one of the legs of the machine, and
containing oil or other suitable liquid.
A pump driven by an eccentric on the shaft before referred to takes
oil from the tank and forces it through two pipes, either to the dies or to
a hose which may be used for conveying the oil or other liquid to nuts
being tapped, stop-cocks or other suitable means being provided on both
pipes for the purpose of controlling the quantity of oil or other liquid
delivered. To the pump there is added an overflow valve, which may be
of the form of an ordinary check valve, with a light spring over the
valve. When the cocks in both pipes are closed, the oil, for example,
delivered from the pump is discharged back into the tank through the
overflow valve. One of the pipes communicates with a stand attached
to the leg in which the before-mentioned recess is formed, the oil passing
through this stand, which is hollow, enters a hollow lever socketed into

page_text: the top of the stand, and then passes into a nozzle which fits the spindle
sufficiently tight to prevent leakage of oil under a very light pressure.
The end of the hollow lever dips into a recess or socket in the nozzle,
whereby the necessity for packing at this part is obviated, but at the
part where the lever is socketed into the top of the stand a light string
packing may be employed to prevent leakage. A prolongation of the
lever is connected by means of a rod with a bell crank latch hinged to
the bed of the machine, which latch engaging with a catch on the clutch
lever of the machine, herein-before referred to, holds such lever back in
the direction it would naturally be forced by the spring on the shaft, and
in this position the dies remain closed. On the clutch lever there is
provided an arm with a counterweight of sufficient amount to draw back
the spring on the shaft, and force the friction clutch on the pinion into
its recess with sufficient force to cause the dies to open. This weight is
held up during the process of cutting by the bell crank herein-before
referred to. In the centre of the spindle there is provided a rod guided at
one end by a loose collar, the other end being held in the nozzle by means
of a split couc and clamping screw. This rod can be clamped with its
end nearest to the dies at any required position back of the dies suited to
the length the bolt is to be threaded; thus if it is set so that its end is
one inch back of the entering face of the cutting dies, when the bolt has
been threaded onc inch from the point, it will come in contact with the
end of the rod. This rod being secured to the nozzle by the cone clamp
and screw as described, forces it back, and thus through the subsidiary
levers and the connecting rod and bell crank it unlatches the clutch
lever, and thus allows the weight to fall, driving back the pinion, and
causing the dies to open for the removal of the bolt. When after its
removal the clutch lever is again latched back, the dies close ready for
the next bolt to be cut.
At the hub of one of the subsidiary levers and the stand there is pro-
vided a coil spring to maintain the stop rod which is in the centre of
the spindle pressed towards the dies and cause the bell-crank latch to
engage with the catch on the clutch lever. In operating the machine,
the dies being adjusted to the proper size of the bolt to be threaded,
the stop rod is fixed in such a position that the latch will be loosened
when the bolt has been threaded the proper distance from the point.
The machine being set in motion, the pump forces oil up through the pipes
to the stand, and then through the hollow levers to the spindle; and

page_text: finally, it flows out of the die box in a steady stream, regulated in
quantity by the stop-cock in the supply pipe. A blank bolt, held in the
usual manner in a holder or clamp sliding on the bed of the machine is
pressed into closed dies; as the dies revolve about the bolt, cutting the
thread, the oil floods the end of the bolt and the cutting dies lubricating
the parts in contact, conveying off the heat and washing out the chips
by its volume or force. When the bolt end, carried on by the screwing
process, reaches the end of the stop rod it actuates the opening gear and
liberates the bolt, while the oil continues to flow out through the dies.
The oil flowing out of the cutter of spindle would accumulate in
the bed or trough of the machine were not some means provided to
carry it back to the tank from which the pump draws its supply. A.
spout, secured to the under side of the bed, is therefore provided, through
which spout the oil and chips may fall and be received on a slanting
platform, where the chips may gather in a pile to be removed at liesure,
while the oil will flow back into the tank.
It will be observed that the devices used to operate the opening
machinery form part of the apparatus used to convey oil from the
tank to the dies. In tapping nuts the lubrication of the die holder is
not required, as it is customary to hold the shank of the tap in the die
box, and present the nuts to be cut to the end of the revolving tap by a
proper sliding nut holder. In this case the cock in one pipe is closed
and the cock in the other pipe opened, the oil being conveyed to the
tap by means of a hose. Bolt threading machines arranged with this
through lubrication may be run at a higher rate of speed than if oiled
in the ordinary manner; but inasmuch as the possible high rate of
rotation is likely to cause the oil to be thrown off from the die box by
centrifugal force, a guard or cover is arranged to surround the dic box,
which serves to catch the oil so thrown off and directs into the trough
of the machine.
It is obvious that this improved method of oiling is also applicable to
all bolt threading machines with revolving dies, whether the dies are
made to open and release the bolt at the end of the cut, or are arranged
as solid dies to be backed off by reversing the direction of rotation;
for example, it may be applied to machines having a solid die for
threading bolts, that is, a die so made as to cut the thread upon the
bolt at one operation with once going over, but requiring to be unscrewed
from the bolt when finished. These dies are usually rotated at the end

page_text: of a hollow mandril, into which mandril the finished threaded end of
the bolt passes as it is cut to a greater or less length. Oil fed into the
back end of the spindle of such machines will be expelled through the
die box, so as to meet the bolt entering the dies, and present all the
advantages of this method of lubrication as claimed for it in its appli-
cation to the Sellers' bolt threading machine. The arrangement of oiler
that permits the oil to gush out from the revolving dies is essentially
different from all the methods of supplying the lubricating fluid; inas-
much as its tendency towards the front of the dies from behind, aided
by the rotation of the die box, spreads the liquid over the cutting edges
and causes them to be continually immersed in the cooling liquid; while
at the same time, as has been before said, the direction of the current
expels the chips as they come from the dics.
The most common form of solid die machine is provided with a
forward-and-back motion actuated by clutches, either friction or positive,
and such machines have frequently been arranged in such a manner,
that when the bolt is threaded a proper distance, suitable devices,
actuated either by the carriage which holds the bolt or the end of the
bolt itself, are made to disengage the clutch from the forward motion
and engage it with the back driving motion.
It is proposed to apply to such machines the central stop rod in com-
bination with the levers which are used to form the connection from the
pump to the spindle.
The oil may be applied to the back of the dies in various ways
without departing from the principle of the Invention. When no stop
motion is required a simple connection by pipe or hose to the back of
the hollow spindle, or to any part of the hollow spindle back of the
dies, whereby the oil will be made to enter back of the dies and flow
around the dies and out of their mouth or holder, will answer the purpose;
this outward flow of the oil in contradistinction to the pouring it on the
bolt or injecting it into the dies from the front forming an important
feature of this Invention.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Henry Johnson in the Great Seal Patent
Office on the 13th January 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of
Middlesex, Gentleman, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Fourteenth day of July, in the year of
our Lord One thousand eight hundred and seventy-four, in the 38th
year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto me, the said John Henry Johnson, Her special license that I,
the said John Henry Johnson, my executors, administrators, and assigns,
or such others as I, the said John Henry Johnson, my executors, admi-
nistrators, or assigns, should at any time agree with, and no others,
from time to time and all times thereafter during the term therein
expressed, should and lawfully might make, use, exercise, and vend,
within the United Kingdom of Great Britain and Ireland, the Channel
Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN SCREW-
CUTTING MACHINES," a communication to me from abroad by Coleman
Sellers, of the City and County of Philadelphia, State of Pennsylvania,
United States of America, upon the condition (amongst others) that I,
the said John Henry Johnson, my executors or administrators, by an
instrument in writing under my hand and seal, should particularly
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 the 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 John Henry Johnson, 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, reference being had to the accompanying
Drawings, and to the letters and figures marked thereon, that is to

page_text: cutting or boit threading machines automatically when the bolt has
been threaded a proper distance from the point.
Second. The providing means for causing a current of lubricating
fluid to pass through the revolving dies in the direction opposite to the
motion of the bolt entering the dies, so as to wash out the chips, to
lubricate the cutting edges, and to keep the dies cool.
Third. The providing means of regulating the supply of the fluid from
a pump to the parts of the machine requiring it, as in threading bolts or
in tapping nuts, and controlling or directing the force of the current so
as to insure the performance of these objects.
The first part of the said Invention is applicable to that class of screw-
cutting or bolt threading machines in which revolving dies open to
liberate the bolt when cut, and it consists in providing an adjustable
stop in the centre of a hollow spindle to be pressed against by the end
of the bolt which is in course of being threaded, and by suitable devices
to actuate the opening machinery and liberate the bolt at the required
time.
The said Invention relates, secondly, to the same class of machines,
and consists in utilizing the levers and devices required for the stop
motion as a means of conveying fluid to the back of the hollow spindle,
and thus causing the flow of liquid from within outward for the purpose
of washing out the chips which otherwise tend to clog up the cutting
parts.
The said Invention consists, thirdly, in arranging the pump which
supplies the liquid with an overflow valve, so that with a constant
amount of delivery by the pump such quantity of the liquid as may be
required can be directed to the parts requiring lubrication.
And in order that the said Invention may be fully understood, I shall
now proceed more particularly to describe the same, and for that purpose
shall select in illustration of the Invention its application to the
description of screw cutting machinery, for which Letters Patent were
granted to Mr. William Sellers, May 3rd, 1859, No. 1109, reference
being had to the several Figures on the annexed Sheet of Drawings, the
same letters and figures of reference on which indicate corresponding
parts in all the Figures..

page_text: Figure 1 represents a sectional clevation of the Sellers' bolt threading
machine with the improvements added. Figure 2 is a plan of the same.
Figure 3 is a rear end elevation. Figure 4 is a sectional front end
elevation, showing the lubricating pump in section; and Figures 5 and 6
are enlarged views of the levers through which the stop motion is
operated, and which convey the lubricating fluid to the dies.
In the machines as ordinarily made the dies A, A, A, are placed in
radial grooves in a cylindrical die box or holder B secured to one end of
a hollow spindle D, to the opposite end of which is attached the driving
spur wheel F. Surrounding the die box B is what is termed a cam box
consisting of cams M, M, M, of equal eccentricity bolted to the annular
projecting end I of the sleeve H, and having other cams P of similar
eccentricity secured to a cover plate O. The rotatory motion of tho
sleeve H back and forth around the spindle D causes the dies A to be
moved in a radial direction, thus opening or closing such dies. To the
sleeve His secured a spur wheel K, smaller in diameter than the spur
wheel F, and the extent of rotation of the sleeve H around the spindle
D is limited by an adjustable stop at u. The spur wheels F and K. are
driven by pinions G and L carried on the shaft E, the pinion G being
fast on the shaft E, whilst the pinion L is loose on such shaft, but is
pressed towards the pinion G by means of a spring b on the shaft E, and
is driven by the friction of the surfaces of a leather disc interposed
between them when brought into action by means of the lever V and
the collar a¹.
The pinion L may be drawn away from the pinion G and caused to
engage in a recess formed in the leg 1, a bevilled collar on the pinion L
fitting this recess after the manner of friction clutches. When the
pinion L is driven by the pinion G it tends by reason of the difference
in diameter of the two pairs of wheels to cause the cam box to rotate-
faster than the die box to the limit allowed by the stop u. This advance
motion of the cam has the effect of closing the dies; but when the
motion of the pinion L is retarded by the friction on the recess in the
leg the dies are caused to open.
The foregoing description explains the operation of the Sellers' bolt
threading machine as ordinarily constructed.
In order more clearly to describe the present Invention I shall employ
numerals to indicate the additional parts.

page_text: To the machines as ordinarily made there is added a tank 1 supported
on one of the legs of the machine, and containing oil or other liquid
used (for convenience I shall describe it as containing oil).
A pump 2 driven by an eccentric on the shaft E takes oil from the
tank, and forces it through pipes 3 and 4 either to the dies or to a
hose 5, which may be used for conveying the oil to nuts in the course of
being tapped; in both of these pipes there are fitted stop-cocks for con-
trolling the quantity of oil delivered. To the pump there is added an
overflow valve 6, which is shown in the form of an ordinary check valve
with a light spring over the valve. When the cocks in both the pipes 3
and 4 are closed the oil delivered from the pump is discharged back into
the tank 1 through the overflow valve 6. The pipe 3 communicates
with a stand 7 attached to the leg ; the oil passing through this stand;
which is hollow, enters a hollow lever 8 socketted into the top of the
stand 7, and then passes into a nozzle 9, which fits the spindle D suffi-
ciently tight to prevent leakage of oil under a very light pressure. It will
be observed that the end of the lever S dips into a recess or socket in the
nozzle 9, whereby the necessity for packing at this part is obviated, but
at the part where the lever 8 is socketted into the top of the stand 7 a
light string packing may be employed for the purpose of preventing
leakage. A prolongation 10 of the lever 8 is connected by means of a
rod 11 with a bell-crank latch 12 hinged to the bed of the machine,
which latch engaging with a catch on the lever V holds the lever V
back in the direction it would naturally be forced by the spring b
on the shaft E, and in this position the dies remain closed. On the
lever V there is provided an arm 13 having a counterweight 14 of
sufficient amount to draw back the spring on the shaft E, and drive the
friction clutch on the pinion L into its recess in the leg with sufficient
force to cause the dies to open. This weight 14 is held up during the
process of cutting by the bell crank 12. In the centre of the spindle D
there is provided a rod 15 guided at one end by a loose collar 16, the
other end being held in the nozzle 9 by means of a split cone 17 and
clamping screw 18. This rod may be clamped with its end nearest to
the dies at any required position at the back of the dies suited to the
length the bolt is to be threaded; thus if it is set so that its end is one a
inch behind the entering face of the cutting dies when the bolt has been
threaded one inch from the point it will come in contact with the end of
the rod 15. This rod being secured to the nozzle 9 by the cone clamp 17.

page_text: and screw 18 forces it back, and thus through the levers 8 and 10 and
the rod 11 and bell crank 12 it unlatches the lever V and allows the
weight 14 to fall, driving back the pinion L and causing the dies
to open for the removal of the bolt. When after its removal the
lever V is again latched back the dies close ready for the next bolt to
be cut.
At the hub of the lever S and the stand 7 there is provided a coil
spring 19 for maintaining the rod 15 pressed towards the dies, and
causing the latch 12 to engage with the catch on the lever V. In
operating the machine, the dies being adjusted to the proper size of bolt
to be threaded, the stop rod 15 is fixed in such a position that the
latch 12 will be loosened when the bolt has been threaded the proper
distance from the point. The machine being set in motion the pump 2
forces oil up through the pipes 3 to the stand 7, and then through the
levers 8 to the spindle; and finally it flows out of the die box in a steady
stream regulated in quantity by the stop-cock in the pipe 3. A blank
bolt held in the usual manner in a holder or clamp sliding on the bed of
the machine is pressed into closed dies. As the dies revolve about the
bolt cutting the thread the oil floods the end of the bolt and the cutting
dies, lubricating the parts in contact, conveying off the heat, and washing
out the chips by its volume or force. When the bolt end, carried on
by the screwing process, reaches the end of the rod 15 it actuates the
opening gear and liberates the bolt, while the oil continues to flow out
through the dies. The oil flowing out of the centre of the spindle would
accumulate in the bed or trough of the machine were not some means
provided for carrying it back to the tank from which the pump draws
its supply. A spout 21 secured to the under side of the bed is therefore
provided, through which spout the oil and chips may fall and be received
on a slanting platform 22, where the chips may gather in a pile to be
removed at leisure, while the oil will flow back into the tank 1.
It will be observed that the devices used to operate the opening
machinery form part of the apparatus used to convey oil from the tank
to the dies. In tapping nuts the lubrication of the die holder is not.
required, as it is customary to hold the shank of the tap in the die box,
and present the nuts to be cut to the end of the revolving tap by a
proper sliding nut holder. In this case the cock in the pipe 3 is closed,
and the cock in the pipe 4 opened, the oil being conveyed to the tap by
means of a hose 5.

page_text: In
The advantage of feeding the oil so that it must necessarily flow
through the dies over the plan in common use of allowing the oil to run
on to the bolt being cut, or at best of injecting it against the face or into
the die box from a pipe on the outside and in front is very great.
the first place it leaves the front of the dies wholly unobstructed by any
kind of oiling device (an important consideration when very short bolts
are being cut close up to the head), and in the second place the lubri-
cation is applied at the very best place possible, that is, where it is most
needed, and by the direction of the current the chips are washed from
the dies. Bolt threading machines arranged with this through lubrica-
tion may be run at a higher rate of speed than when oiled in the
ordinary manner; but inasmuch as the possible high rate of rotation
is a tendency to cause the oil to be thrown off from the die box by
centrifugal force a guard or cover 20 is arranged to surround the die box
for the purpose of catching the oil so thrown off and directing into the
trough of the machine.
In describing this improved method of oiling it has been shown as
applied to the Sellers' machine, but it is obvious that it is also applicable
to all bolt threading machines with revolving dies, whether the dies are
made to open and release the bolt at the end of the cut, or are arranged
as solid dies to be backed off by reversing the direction of rotation. For
example, it may be applied to machines having a solid die for threading
bolts, that is, a die so made as to cut the thread upon the bolt at one
operation with once going over, but requiring to be unscrewed from the
bolt when finished. These dies are usually rotated at the end of a hollow
mandril, into which mandril the finished threaded end of the bolt passes
as it is cut to a greater or less length. Oil fed into the back end of the
spindle of such machine will be expelled through the die box so as to
meet the bolt entering the dies, and present all the advantages of this
method of lubrication as claimed for it in its application to the Sellers'
bolt threading machine. The arrangement of oiler that permits the oil
to gush out from the revolving dies is essentially different from all the
methods of supplying the lubricating fluid, inasmuch as its tendency
towards the front of the dies from behind, aided by the rotation of the
die box, spreads the liquid over the cutting edges, and causes them to be
continually immersed in the cooling liquid; while at the same time, as
has been before stated, the direction of the current expels the chips as
they come from the dies.

page_text: The most common form of solid die machine is provided with a forward
and back motion actuated by clutches, either friction or positive, and
such machines have frequently been arranged in such a manner that
when the bolt is threaded a proper distance, suitable devices, actuated
either by the carriage which holds the bolt or the end of the bolt itself,
are made to disengage the clutch from the forward motion and engage it.
with the back driving motion.
According to the present Invention the central stop rod is applied to
machines of this description in combination with the levers which are
used to form the connection from the pump to the spindle; but in
regard to this application of the stop motion as a means of accomplishing
the double purpose I wish it to be understood that I do not confine
myself for the application of oil at the back of the dies to the manner
described, or to any of the devices as described, as the same result may
be accomplished in various ways without departing from the principle of
the Invention. When no stop motion is required a simple connection
by pipe or hose to the back of the hollow spindle or to any part of the
hollow spindle at the rear of the dies, whereby the oil will be made to
enter at the back of the dies and flow around the dies and out of their
mouth or holder will answer the purpose. This outward flow of the oil
in contradistinction to the pouring it on the bolt or injecting it into the
dies from the front forming an important feature of this present
Invention.
Having now described and particularly ascertained the nature of the
said Invention, and the manner in which the same is or may be used or
carried into effect, I would observe in conclusion that what I consider to
be novel and original and therefore claim as the Invention secured to
me by the herein-before in part recited Letters Patent is,―
First. The combination with a bolt threading machine of a lubricating
pump and an overflow valve, substantially as and for the purposes herein-
before described and as illustrated by the accompanying Drawings.
Second. The combination with a pump and overflow valve of the
regulating cocks or their equivalent, substantially as and for the
purposes herein-before described and as illustrated by the accompanying
Drawings.
Third. The combination with the central adjustable stop 15 of the
conical clamp 17, adjusting nut 18, sleeve 9, and lever S, or its equiva-

page_text: lent, substantially as and for the purposes herein-before described, and
as illustrated by the accompanying Drawings.
Fourth. The combination of the central adjustable stop 15 with the
levers or their equivalents for releasing the opening mechanism of the
dies, substantially as herein-before described and illustrated by the
accompanying Drawings.
Fifth. The combination with a hollow spindle and revolving dies of a
duct through which the lubricant is introduced to the rear of the dies.
Sixth. The combination of a reservoir below the cutting dies, and a
duct through which the lubricant is conveyed from the reservoir to the 1
rear of the dies, substantially as herein-before described and illustrated
by the accompanying Drawings.
Seventh. The combination of a reservoir below the cutting dies, a duct
through which the lubricant is conveyed from the reservoir to the rear of
the dies, and a duct which conveys the lubricant after it passes through
the dies back to the reservoir.
In witness whereof, I, the said John Henry Johnson, have to
this my Specification set my hand and seal, this Eleventh day of
January One thousand eight hundred and seventy-five.