IMPROVEMENTS IN THE MANUFACTURE OF FILES, TAPS, DIES AND OTHER CUTTING TOOLS AND IN APPARATUS THEREFOR
Year: 1883

page_text: LETTERS PATENT to Henry Harris Lake, of the firm of Haseltine, Lake, and
"
Co, Patent Agents, Southampton Buildings, London, for an Invention of
"IMPROVEMENTS IN THE MANUFACTURE OF FILES, TAPS, DIES AND OTHER
CUTTING TOOLS AND IN APPARATUS THEREFOR communicated to him from
abroad by Martin Armstrong Howell, Junior, of Chicago, Illinois, United States
of America, Gentleman
.
PROVISIONAL SPECIFICATION left by the said Henry Harris Lake at the
Office of the Commissioners of Patents on the 6th March 1883.
HENRY HARRIS LAKE, of the firm of Haseltine, Lake, and C, Patent Agents,
Southampton Buildings, London, "IMPROVEMENTS IN THE MANUFACTURE OF
FILES, TAPS, DIES AND OTHER CUTTING TOOLS AND IN APPARATUS THEREFOR
[A communication to him from abroad by Martin Armstrong Howell, Junior, of
Chicago, Illinois, United States of America, Gentleman]
This invention relates to certain improvements in the manufacture of files and
other cutting tools from cast iron, in contradistinction to those heretofore made
from forged metal, whether the same be forged steel or wrought iron subsequently
converted; and to apparatus therefor
The object of the said invention is to effect an improvement in the manufacture
by casting the blanks from white cast iron, softening or annealing the same in
contact with oxides or other matter having an affinity for carbon, if an excess of
carbon is present; surfacing and cutting the same while in this annealed condition
and finally by converting and cooling the same in an atmosphere of hydro-carbon,
where all traces of oxygen are kept excluded to the end of the operation
In the specification of former Letters Patent dated December 21 AD 1881.
N° 5602 for "Improvement in the manufacture of files," the communicator of this
invention has described and claimed a process of decarburizing cast iron blanks,
in the manufacture of files, whereby the original granular condition of the metal is
retained, and all forging or change of structure of the metal is avoided. By the
process of recarburizing alluded to in said former specification it has been found
מי
1

page_text: that the result is imperfect and unreliable, through the leakage and loss of the
hydro-carbon vapors in the boxes from their expansion before the metal blanks,
reached a point in heating sufficient to saturate the metal, as the generation of the
gases of hydro carbons begins long in advance of the maximum heating point of
the metal and force an escape and are wasted, no matter how securely the box is
or may be bound or sealed, and when the maximum heating point of the metal is
reached, the saturation is very imperfect or wholly defeated through the want of
the hydro carbon vapor.
In order therefore to obviate this difficulty and to accomplish my object success-
fully and obtain a true carburet of iron I proceed as follows according to the
present invention, that is to say
I take the blanks which are cast in the usual way, and if an excess of carbon is
present, I remove the excess by cementing in oxides, or other matter, having an
affinity for carbon, or if no excess of carbon is present, they are simply annealed or
softened by any of the well known methods, in sand, carbonate of lime, etc. The
annealed blanks are then finished by grinding, shaping and cutting, no forging or
hammering being allowed. The finished blanks being now granular in structure
can be saturated more readily with carbon, as when heated to a high degree, the
metal is more easily penetrated than if fibrous or forged.
I therefore place the blanks in a retort or flask of wrought or cast iron but
preferably of an alloy of iron and nickel, to avoid oxidation of the flask at a high
heat, the relative proportions in which these two metals enter into said alloy, being
preferably as follows, viz: 1 part, of nickel to 4 or 5 parts of iron. This flask is
constructed with a tapered collar surrounding its mouth and is provided with a
close fitting cover tapered or flaring upon its internal diameter outwardly to fit said
collar which is luted and clamped firmly in place by means of a spring clamping
yoke engaging with the shouldered collar and a screw engaging with said yoke and
bearing against the cover, thereby sealing the mouth of said flask and securing the
contents from leakage of air, or loss of hydro carbon vapor. In one end of the
flask is a supply pipe or tube provided with a cock for controlling the flow of
the vapors or gases, said tube being jointed near the cock, so that it can be
disconnected when removed. In addition to this supply tube, and connecting with
the flask, is a small vent cock or escape. The flask thus prepared and charged is
then placed in the furnace, or in a muffle; the vent cock is opened and a current
of hydro-carbon gas is driven into the flask through the pipe or tube mentioned,
until all air or oxygen contained in the flask when charged, is driven out, which is
determined by the lighting of the escaping vapor at the small vent cock. This cock
is now closed until the proper heat is reached to saturate the metal to the necessary
limit, or to deoxidize any graphitic or oxidated carbon which shall have remained
in the metal during the annealing stage: The vent cock is now opened to admit
its being lighted sufficiently to preserve proof of its freedom from oxygen to the
workman, and to give a slight motion to the current of vapor passing in at the
supply pipe. The pressure is now increased at the gas holder, and retained until
the operation is completed. When the vents are closed the supply pipe is shut off
and detached leaving the contents in an atmosphere of pure hydro-carbon. The
flask is then removed to cool in this condition, being replaced immediately by
another to the same end.
In some cases where no means are at hand to manufacture hydro carbon gas for
this purpose, and in order to economize the operation, I interlay or stratify the
blanks in vegetable or animal carbon saturated with oils or other hydro carbon, or
place in the flask any good hydro-carbon. The supply pipe or tube is then con-
nected with a small gas holder, or india rubber bag or any suitable receptacle
which is capable of holding vapors or gases. The retort or flask is then placed in
the furnace. The advancing heat soon produces a generation of hydro-carbon
gas within the flask The first vapors being now intermingled with air already in
the flask are allowed to flow off through the small vent cock until pure hydro-
carbon alone remains, when the vent cock is closed and the cock of the supply tube

page_text: opened. The rapidly generating gases now flow off-through the tube to the gas
holder which has previously been exhausted of air, where they are stored up for
return and use, as soon as the heat of the metal has reached the maximum, when it
is returned and kept under pressure as in the previous operation to the end.
It will be seen that as no oxygen is allowed in contact with the metal, no possible
oxidation results, as by the processes formerly in use. That from the beginning of
the heating to the end of the cooling, they are enveloped by the hydro-carbon
vapor, and the result is, a true carbide of iron, which gives to the product greater
durability than steel, or any product liable to oxidation as by the ordinary
processes.
It is easily seen that one of the novel features of this improvement lies in the
use of removable flasks, which hold the metal while cooling in a carbon vapor.
It will also be noticed that part of the process described, viz; the decarburization
and subsequent recarburization of iron, is not new, and to this as heretofore
practised I lay no claim. That the use of hydro-carbon gas in the converting of
iron to steel has been frequently practised, but in such cases the red hot bars were
withdrawn from the retort which was stationary, and subjected to oxidation while
being rolled or forged.
I may employ two forms for the body of the flask, one being square and the
other round. Although either may be used, still, I prefer the square bodied flask,
since it is more convenient to charge, and holds a greater number of files.
Moreover it admits of the articles being laid in more regularly and evenly than in
the round flask.
:
In order that it may more readily be understood what I mean by a true carburet
of iron, I will explain.
Where the carbon is wholly combined in the metal, as in true white iron, we
have a true carburet, extremely hard and refractory and oxidated only at extreme
heats. Steel has always been considered by scientists as a true carburet. This I
think is an error which I will explain. In steel of commerce we find part of
the carbon combined and part crystallized between the fibres or particles of iron.
This is the result of too low a heat in casting the cemented iron. In proof of this
assertion, if we thoroughly anneal a bar of steel, and break it, we will find the free
or graphitic carbon crystals between the fibres or particles. This is an oxidated
condition, and from this fact, I consider steel not a true carbide, but an oxidated
carbide, susceptible to "burning" as is too well known, at a low heat compared to a
true carbide. The cause of the oxidated condition of this, as well as all other
graphitic carbon in iron, arises from the expansion of this free carbon between the
particles of heated metal, which destroys its cohesion, renders it very porous, while
heated, and allows the surrounding atmosphere to penetrate every part of the
expanded metal, thereby causing an oxidation of the free carbon, which is shown
by its change of color to black graphitic carbon, soft and easily fusible at a moderate
heat.
In the case of a true carburet as we find it in true white iron, there being no freė
carbon present, annealing produces no like result, nor can oxidation of its carbon
take place below the point of fusion, which alone admits of the liberation of its
carbon, while in most cases the heat required is much beyond the fusion point.
This carbon by its colorless character, shows the characteristics of true carbon, and
its extreme hardness combined with its colorless character gives it a near approach
to carbon as we find it in the diamond. The superior qualities therefore of a true
carburet for files and cutting tools cannot be over estimated.
It will be noticed that the process of cutting as in the case of the teeth of files is
performed after the grinding and shaping of the blanks, and subsequently converted,
This is preferably the routine of my operation. There may be, however, some cases
in which it is better to convert or carburize the ground or surfaced blank first,
which can be subsequently cut, preparatory to hardening or tempering, which is
done by any of the usual methods well known

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Henry Harris Lake in the Great Seal Patent Office on the
6th September 1883.
"
HENRY HARRIS LAKE, of the firm of Haseltine, Lake, and C Patent Agents,
Southampton Buildings, London, "IMPROVEMENTS IN THE MANUFACTURE OF
FILES, TAPS, DIES, AND OTHER CUTTING TOOLS, AND IN APPARATUS THEREFOR
A communication to me from abroad by Martin Armstrong Howell, Junior of
Chicago, Illinois, United States of America, Gentleman.
This invention relates to certain improvements in the manufacture of files and
other cutting tools from cast iron, in contradistinction to those heretofore made
from forged metal, whether the same be forged steel or wrought iron, subsequently
converted, and to apparatus therefor
The object of the said invention is to effect an improvement in the manufacture
by casting the blanks from white cast iron, softening or annealing the same in
contact with oxides, or other matter having an affinity for carbon, if an excess of
carbon is present; surfacing and cutting the same while in this annealed condition
and finally by converting and cooling the same in an atmosphere of hydro-carbon,
where all traces of oxygen are kept excluded, to the end of the operation.
In the accompanying drawing.
Figure 1 is a central longitudinal section taken through the flask used in the
manufacture of the said files or the like and forming part of this invention, the
attachments connected therewith being shown in elevation.
Figures 2 and 3 are transverse sections of Figure 1 just behind the shoulder of
the tapered collar which surrounds the mouth of the flask, showing different forms
of the body portion.
Figure 4 is a view of a carbureted cast iron file of any ordinary pattern, produced
by means of this invention.
Figure 5 is a view of a carbureted cast iron tap, produced by means of this
invention; the corresponding die being shown in the lower part of the said figure,
both tap and die being of any ordinary pattern.
In the specification of former Letters Patent dated December 21 A D 1881,
N° 5602, for "Improvements in the manufacture of files," the communicator of this
invention has described and claimed a process of decarburizing cast iron blanks, in
the manufacture of files, whereby the original granular condition of the metal is
retained, and all forging, or change of structure of the metal is avoided By the process
of recarburizing alluded to in said former specification it has been found that the
result is imperfect and unreliable, through the leakage and loss of the hydro-carbon
vapors in the boxes from their expansion before the metal blanks reached a point
in beating sufficient to saturate the metal, as the generation of the gases of hydro-
carbons begins long in advance of the maximum heating point of the metal and
force an escape and are wasted, no matter how securely the box is or may be bound
or sealed, and when the maximum heating point of the metal is reached, the
saturation is very imperfect or wholly defeated through the want of the hydro
carbon vapor. In order therefore to obviate this difficulty and to accomplish my
object successfully and obtain a true carburet of iron. I proceed as follows according
to the present invention that is to say
I take the blanks which are cast in the usual manner, and if an excess of carbon
is present, I remove the excess by cementing in oxides, or other matter, having an
affinity for carbon, or if no excess of carbon is present, they are simply annealed
or softened by any of the well known methods, in sand, carbonate of lime, or the

page_text: like. The annealed blanks are then finished by grinding, shaping and cutting,
no forging or hammering being allowed. The finished blanks being now granular
in structure can be saturated more readily with carbon, as when heated to a high
degree, the metal is more easily penetrated than if fibrous or forged
I therefore place the blanks in a retort or flask of wrought or cast iron, but
preferably of an alloy of iron and nickel, to avoid oxidation of the flask at a high
heat, the relative proportions in which these two metals enter into the said alloy,
being preferably as follows that is to say:-1 part of nickel to 4 or 5 parts of iron.
This flask A which is shown in Figure 1 is constructed with a tapered collar B
surrounding its mouth, and is provided with a close fitting cover C tapered or
flaring upon its internal diameter outwardly to fit the said collar which is luted
and clamped firmly in place by means of a spring clamping yoke D engaging with
the shouldered collar B, and a screw E engaging with the said yoke and bearing
against the cover, thereby sealing the mouth of the said flask and securing the
contents from leakage of air, or loss of hydro carbon vapor. In one end of the
flask is a supply pipe or tube F provided with a cock f for controlling the flow of
the vapors or gases, the said tube being jointed near the cock, so that it can be
disconnected when removed. In addition to this supply tube, and connecting with
the flask, is a small vent-cock or escape G. The flask thus prepared and charged
is then placed in the furnace, or in a muffle; the vent cock f is opened and a
current of hydro-carbon gas is driven into the flask through the said pipe or tube F,
until all air or oxygen contained in the flask when charged, is driven out, which is
determined by the lighting of the escaping vapor at the vent cock G. This cock
is now closed until the proper heat is reached to saturate the metal to the
necessary limit, or to deoxidize any graphitic or oxidated carbon, which shall have
remained in the metal during the annealing stage. The vent cock G is now
opened to admit its being lighted sufficiently to preserve proof of its freedom from
oxygen to the workman, and to give a slight motion to the current of vapor
passing in at the supply pipe. The pressure is now increased at the gas holder H,
and retained until the operation is completed. When the vents are closed the
supply pipe F is shut off and detached, leaving the contents in an atmosphere of
pure hydro carbon The flask is then removed to cool in this condition, being
replaced immediately by another to the same end.
In some cases where no means are at hand to manufacture hydrocarbon gas for
this purpose, and in order to economize the operation, I interlay or stratify the
blanks in vegetable or animal carbon saturated with oils or other hydrocarbon, or
I place in the flask any good hydro-carbon. The supply pipe or tube F is then
connected with a small gas holder, or india rubber bag H, or any suitable
receptacle which is capable of holding vapors or gases. The retort or flask is
then placed in the furnace. The advancing heat soon produces a genèration of
hydro carbon gas within the flask. The first vapors being now intermingled with
air already in the flask are allowed to flow off through the vent cock G until
pure hydro-carbon alone remains, when the vent cock is closed, and the cock f of
the supply tube F opened. The rapidly generating gases now flow off through the
tube to the gas holder H, which has previously been exhausted of air, where they
are stored up for future use. As soon as the heat of the metal has reached the
maximum, the gas is returned and kept under pressure, as in the previous operation,
to the end.
It will be seen that as no oxygen is allowed in contact with the metal, no
possible oxidation results, as by the processes formerly in use, and that from the
beginning of the heating to the end of the cooling, it is enveloped by the hydro-
carbon vapor, and the result is, a true carbide of iron, which gives to the product
greater durability than steel, or any product liable to oxidation, as by the ordinary
processes.
It is easily seen that one of the novel features of this improvement lies in the
use of removable flasks, which hold the metal while cooling in a carbon vapor.
It will also be noticed that part of the process described, namely the

page_text: decarburization and subsequent recarburization of iron, is not new, and to this as
heretofore practised I lay no claim; and that the use of hydro-carbon gas in the
converting of iron to steel has been frequently practised, but in such cases the red
hot bars were with drawn from the retort which was stationary, and subjected to
oxidation while being rolled or forged.
In Figures 2 and 3 of the drawing I show two forms for the body of the flask,
one being square and the other round. Although either may be used, still I prefer
the square bodied flask, since it is more convenient to charge, and holds a greater
number of files. Moreover it admits of the articles being laid in more regularly
and evenly than in the round flask.
In order that it may more readily be understood what I mean by a true carburet
of iron, I will explain.
Where the carbon is wholly combined in the metal, as in true white iron, we
have a true carburet, extremely hard and refractory, and oxidated only at extreme
heats. Steel has always been considered by scientists as a true carburet. This I think
is an error, which I will explain. In steel of commerce we find part of the carbon
combined and part crystallized between the fibres or particles of iron. This is
the result of too low a heat in casting the cemented iron. In proof of this
assertion, if we thoroughly anneal a bar of steel and break it, we shall find the
free or graphitic carbon crystals between the fibres or particles. This is an
oxidated condition, and from this fact I consider steel not a true carbide, but an
oxidated carbide, susceptible to "burning" as is too well known, at a low heat
compared to a true carbide. The cause of the oxidated condition of this, as well as
all other graphitic carbon in iron, arises from the expansion of this free carbon
between the particles of heated metal, which destroys its cohesion, renders it very
porous, while heated, and allows the surrounding atmosphere to penetrate every
part of the expanded metal, thereby causing an oxidation of the free carbon, which
is shown by its change of color to black graphitic carbon, soft and easily fusible at
a moderate heat.
In the case of a true carburet as we find it in true white iron, there being no
free carbon present, annealing produces no like result, nor can oxidation of its
carbon take place below the point of fusion, which alone admits of the liberation of
its carbon, while in most cases the heat required is much beyond the fusion point.
This carbon by its colorless character, shows the characteristics of true carbon,
and its extreme hardness combined with its colorless character gives it a near
approach to carbon as we find it in the diamond. The superior qualities therefore
of a true carburet for files and cutting tools cannot be over-estimated.
It will be noticed that the process of cutting, as in the case of the teeth of files,
is performed after the grinding and shaping of the blanks, which are subsequently
converted. This is preferably the routine of this operation. There may be,
however., some cases in which it is better to convert or carburize the ground or
surfaced blank first, which can be subsequently cut, preparatory to hardening or
tempering, which is done by any of the usual methods well known.
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
First. In the manufacture of files, taps, dies, and other cutting tools, the
annealing or decarburization, cutting and finishing of the cast iron blanks, and
their subsequent conversion into a true carburet in a sealed flask from which all
atmospheric air or traces of oxygen are expelled, the said flask being connected by
a pipe with a gas-holder in which the vapors of hydro-carbons are stored under
pressure until the maximum degree of temperature is reached at which point
conversion begins, the said sealed flask being subequently removed and allowed
to cool before it is opened, whereby all danger of oxidation of its contents is
avoided
Second. A removable converting flask or retort, having a tapered collar
surrounding its mouth, a cover having a corresponding taper or flare on its inner

page_text: face, and a clamp or other suitable device, whereby the cover is driven upon, and
held in engagement with, the tapered collar, the said cover being provided with a
section of tubing, whereby the interior of the flask may be connected with a
suitable gas-receiver.
Third. Carbureted cast iron files, taps, dies and other cutting tools, substantially
as described.
Fourth. A converting or carburizing flask or retort, constructed from an alloy of
iron and nickel, in the manner substantially as described.
In Witness whereof I the said Henry Harris Lake have hereunto set my
hand and seal this Fifth day of September in the year of our Lord One thousand
eight hundred and eighty three.
HENRY H LAKE (L.S.)