IMPROVE- MENTS IN THE METHOD OF HEATING, HARDENING, AND TEMPERING VARIOUS ARTICLES MADE OF STEEL, OR OF IRON AND STEEL COMBINED
Year: 1846

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALFRED
VINCENT NEWTON, of the Office for Patents, 66, Chancery Lane, in the County
of Middlesex, Mechanical Draughtsman, send greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent under the Great Seal of Great Britain, bearing date
at Westminster, the Twenty-fourth day of September, in the tenth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said Alfred Vincent Newton, Her especial licence, full power, sole
privilege and authority, that I, the said Alfred Vincent Newton, my executors,
administrators, and assigns, and such others as I, the said Alfred Vincent
Newton, my executors, administrators, or assigns, should at any time agree
with, and no others, from time to time and at all times during the term of
years therein mentioned, should and lawfully might make, use, exercise,
and vend, within England, Wales, and the Town of Berwick-upon-Tweed,
and in all Her Majesty's Colonies and Plantations abroad, and in the Islands
of Jersey, Guernsey, Alderney, Sark, and Man, an Invention of "IMPROVE-
MENTS IN THE METHOD OF HEATING, HARDENING, AND TEMPERING VARIOUS ARTICLES
MADE OF STEEL, OR OF IRON AND STEEL COMBINED," being a communication from
a Foreigner residing abroad; in which said Letters Patent is contained
a proviso obliging me, the said Alfred Vincent Newton, by an instrument in
writing under my hand and seal, particularly to describe and ascertain the
nature of the said Invention, and in what manner the same is to be
performed, and to cause the same to be enrolled in Her Majesty's High

page_text: Court of Chancery within six calendar months next and immediately after
the date of the said in part recited Letters Patent, as in and by the same,
reference being thereunto had, will more fully and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
Alfred Vincent Newton, do hereby declare that the nature of the said Invention,
and the manner in which the same is to be performed, is particularly described
and ascertained in and by the following description thereof, reference being
had to the Drawings hereunto annexed, and to the letters and figures marked
thereon (that is to say).:-
This Invention, as communicated to me by my Foreign Correspondent,
consists in the construction and application of certain apparatus, which, with
ordinary care, will insure the proper heating of articles which are intended to be
hardened or tempered. The apparatus represented in the Drawings which accom-
pany the Specification were designed principally for the heating, hardening,
and tempering of axes; but under proper modifications, which will readily suggest
themselves to any competent workman, every variety of article requiring to be
'submitted to such processes may be treated according to this Invention. The
heating is effected in such a manner as to insure the bringing of the articles
to a degree of temperature which shall be equable throughout, and to vary
this temperature as the nature of the steel may require; and the method of
"hardening the articles so heated is such as to render them more uniform in
hardness than has been attained by any of the means heretofore adapted.
For heating the axes or other articlos which may be suitable thereto in form
or size, a heating furnace is constructed in the form of a vertical cylinder.
The exterior of this cylinder may be made of sheet iron, say four feet eight
inches in diameter, or varying therefrom in such a degree as shall give to its
'interior a diameter of four feet when lined with fire brick. Its height may be
about three feet. In the interior of this cylinder several fire chambers are
formed, the number of which is usually four, dividing the cirele of brick lining
into eight equal parts, so that there shall be a space of fire brick between each
of the fire chambers. The inner wall of each fire chamber is formed by a
circle of three feet four inches in diameter; each of the fire chambers is
therefore about eighteen inches long, about four inches from front to back, or
from one of its circular sides to the other, and it may be about four inches
also in depth; the ends of each of the chambers may be parallel or nearly so.
'Under each there are grate bars, and air is supplied to them through a pipe
connected with a blowing apparatus. A circular table, usually of cast iron,
three feet four inches in diameter (which is the same with that of the interior
circle of the fire chambers) is made to revolve slowly on a level with the upper

page_text: part of the said chambers. This table is sustained on a central shaft which
passes down through the bottom of the furnace, and has its bearing in a step
below it; a pulley keyed on to this shaft serves to communicate rotary motion
to the table. When the axes or other articles are to be heated they are placed
upon the table with their bitts or steeled parts projecting so far over its edge
as to bring them directly over the centre of the fire, and the table on which
they are thus situated is kept slowly revolving during the whole time of
heating, the time required being governed by the size of the article under
operation. When duly heated they are ready for the process of hardening.
The hardening bath consists of a circular tub or vat, wherein the hardening
liquor (usually composed of water containing salt) is placed. Within this tub
or vat, a little above the surface of the liquid, is a whee', mounted horizontally,
and made to revolve by means of a hand and pulley. Around the periphery
of this wheel a number of hooks or pins are provided, upon which the axes or
other articles are to be suspended as they are taken from the furnace; the
height of these pins from the liquid is such as will allow the lower part only,
or bitt, to be immersed therein. The temperature of the hardening liquor is
kept down by having a large reservoir thereof in the ground below the tub or
vat, from which reservoir fresh liquor is pumped into it as required, and that
which has been heated is allowed to flow back again into the said reservoir,
which being a few feet below the surface of the ground, and of considerable
capacity, preserves the liquor at a sufficiently low temperature.
As soon as
the hardening of the steeled portion is effected, the axes or other articles are
removed from the hooks or pins, and the heads are cooled by dipping them in
cold water.
In Sheet I. of the accompanying Drawings Figures 1 and 2 represent in
perspective views the furnace and the hardening tub. Figure 3 is a plan view
of the interior of the furnace, the upper part or top plate thereof being
removed; and Figure 4 is a vertical section taken in the line × . . . . x of
Figure 3. A, A is the furnace. B, B, are the furnace doors, through which
the fires are fed, and the articles to be hardened are adjusted. C is the
chimney for carrying off the gases of combustion, and D the pipe for supplying
air to the fire. E, E, are the fire chambers. F the revolving table, upon
which the axes or other articles to be heated are placed. G is a vertical
shaft, provided with a winch handle, and carrying a pulley H, which, by
means of an endless band I, communicates rotary motion to the pulley on the
shaft which supports the table F, and thus causes it to revolve. J, Figure 2,
is the hardening tub. K, a wheel, mounted horizontally in the tub J, and
furnished on its periphery with pins or hooks a, a, upon which to hang the

page_text: axes or other articles. This wheel may be kept revolving by means of an
endless band L passing round a pulley M on the shaft G, and also round a
pulley on the shaft of the wheel K.
It is well known to persons intimately acquainted with the manufacturing
of edge tools, that the most difficult part of the operation of hardening and
tempering is the giving of a uniform and proper degree of heat to the piece.
to be hardened. The exact degree of heat to be given will, it is true; vary:
according to the nature of the steel to be operated upon, as what is called.
high steel will require to be less highly heated than what is known as low
steel, the experience and judgment of the operator being the only guide in this
particular. But whatever be the quality of the steel, the equal heating of all.
its parts is of the utmost importance; and in articles of any considerable size
this cannot be effected in the ordinary mode of procedure with an open fire..
Where articles are unequal in thickness, as is usually the case, the difficulty
is much increased, but even where the thickness is equal the difficulty is not
removed. When the articles to be heated are placed over an open fire, one
side of the steel is exposed to its action, and the other in greater or less degree
to that of the atmosphere, and the utmost care and skill cannot entirely over-
come the unequal heating resulting therefrom. In the apparatus which forms
the subject of the present Invention, all parts of the steel may be equally
exposed to the action of the fire, the intensity of which may be increased as
the articles become heated, and all danger of heating the thin more highly
than their thicker parts is removed; they are consequently equally expande
in all their parts, and the danger of producing cracks or other injurious effects
from unequal contraction in hardening, which often destroys the tools, does
not exist. I am fully aware that articles of a small size have been heated in
closed boxes; that others have been enclosed in powdered charcoal or other
substances; but these processes are inapplicable to axes, and to many other
articles which may be advantageously heated by means of this apparatus, and
the difference of the process and means will be obvious to all who are
practically acquainted with the working of metals.
It has been already stated that the apparatus, as herein described, is so
formed as to adapt it to the heating and hardening of axes. To these the
Table F is particularly adapted; but for the support and exposure of other
articles to the action of the fire the outer edge of the table must be furnished
with devices adapted to them in a manner that will occur to any competent
workman. The improved method of tempering articles manufactured in
whole or in part of steel is similar to that above described for heating such
articles for hardening, and consists in the placing them, and keeping them for

page_text: a sufficient length of time, in an atmosphere or bath of heated air, which
bath is to be brought up to and kept at the temperature required for the
tempering, and which will vary according to the nature of the steel employed,
and of the tool or other article to be tempered. To effect this object the
Inventor constructs an oven, which may be formed of iron or other material,
and with this oven a furnace and air-flues are so connected and arranged
that the air contained in the oven may be as highly heated as is deemed
necessary, whilst its temperature can be regulated by the introduction of cold-
air at any time. For the purpose of ascertaining the temperature of the oven
a thermometer is employed, the bulb of which is to be exposed to the action of
the air contained in the oven. The articles to be tempered may be placed on
a carriage or wheel, which may be made to revolve or move within the oven,
by which the air will be in some degree agitated, and the articles to be
A device
operated upon will be made to occupy different parts of the oven.
of this kind may not be absolutely necessary, but it is undoubtedly useful and
convenient.
The structure which I will now describe is intended for the temporary of
common axes, but will answer perfectly well for edge tools, swords, and
cutlery of all kinds, and for a variety of other articles for some purposes;
however, it may be found necessary to vary the particular structure of the
oven whilst the principle of action remains the same.
In Sheet II. of the accompanying Drawings Figure 5 represents in per-
spective view an oven and furnace constructed for the above-named furnace.
Figure 6 is a vertical cross section of the same, and Figure 7 represents the
manner of arranging a horizontal wheel, upon which the axes or other articles
are to be placed within the oven, so that the whole may be made to revolve.
N is the oven set immediately above the surface O, the heat from which
Q is the escape
passes through the flue space P, P, surrounding the oven.
flue for the heated gases. R is an open tube leading from the interior of the
oven to the external air, and through this a thermometer is passed in such a
manner that its bulb shall indicate the temperature of the air within the oven.
S is a thermometer placed within this tube. T is a blast pipe through which
air is to be conveyed to the ash pit of the furnace from any convenient blowing
apparatus. From this the tube U leads into the ash pit to supply the air
necessary to combustion. V is a tube leading also from the tube T into the
oven, and through which cold air may be blown when the temperature of the
oven is to be reduced, or the same may be effected in other modes, as by the
The
opening of the door, which has been found sufficient in practise.
tubes U and V are furnished with stopcocks to regulate the passage of air

page_text: through them. This mode of tempering will apply equally to tools which
have been hardened, whatever may be the process of hardening. W,
Figures 6 and 7, is a horizontal wheel placed on an axis X, and made to
revolve by means of bevil gearing, as shewn at Y, the axis and winch Z
serving to communicate the desired motion. b and c are bars placed within
the oven, and made fast to its ends to sustain the axis X. When axes are
to be tempered I place them on their heads or poles around the wheel W,
which may be furnished with projecting pins to keep them in place. In the
oven which I have assayed the wheel W is about twenty inches in diameter,
and holds conveniently three dozen axes, but the oven may be adapted to a
much larger number: The articles to be heated are passed into the oven
through the doorway P¹, and when properly arranged on the wheel W, the
door is closed, and the wheel is made to revolve slowly. During the operation
there will be a continuous current of air passing out through the tube R,
which current will cause the thermometer contained in the tube to shew the
exact temperature of the air within the oven. With the best cast steel a tem-
perature of five hundred and ten degrees of Fahrenheit's scale has been found
to produce a perfectly good result in the tempering of axes, and the time
required to bring them up to this degree of heat is about forty-five minutes.
Double or treble or a larger number may be tempered in the same space of
time if the oven is sufficiently large. For smaller articles less time will be
required, and that in proportion to their substance. No injury has been found
to result from keeping the articles longer in the oven than is actually neces-
sary when the temperature was maintained at the same degree, a thing in
which there is not the slightest difficulty under the foregoing arrangements.
It will be manifest, also, that the temperature of the oven may be graduated
so as to suit high or low steel, as well as to adapt it to the degree of hardness
required in the articles operated upon. This process is entirely free from the
uncertainty resulting from the test of colour so generally relied upon, and also
from the varying fusibility of metallic alloys, which have sometimes been used
for tempering. The oven, as above described and represented in the Drawing,
is constructed of iron, and for those of a small size it may be best to form
them of this material, but they may be constructed also in whole or in part of
brick or stone, which are bad conductors of heat, and their form may be varied
in
any convenient manner. If built entirely of bricks or other bad conductor
of heat, it may be found advisable to introduce heated air by means of air
tubes passing through the furnace, as well as to provide the means of intro-
ducing cold air. This and other changes in the arrangement of the parts may
be made according to the choice or judgment of the constructor.

page_text: Having thus fully described the nature and operation of the apparatus for
heating, hardening, and tempering various articles made of steel, or of iron
and steel combined, as communicated to me by my Foreign Correspondent, I
wish it to be understood that, under the above in part recited Letters Patent,
I claim,-
First, the manner herein set forth of constructing the heating furnace with
an enclosed fire, and having four or any other convenient number of fire
chambers arranged circularly around or under the top of a table, which is
adapted to receive the articles that are to be heated upon it, and which is
made to revolve during the time of heating, substantially in the manner and
for the purpose herein set forth.
Secondly, I claim, in combination with the heating oven, the apparatus
herein described for hardening the article thus heated, the said apparatus
consisting of a revolving wheel situated above the surface of the hardening
liquid, the said wheel being furnished with pins, hooks, or other devices suited
to the particular articles to be operated upon, the whole being arranged
substantially as described.
Thirdly, I claim the manner herein set forth of tempering articles formed
in whole or in part of hardened steel by the action of air heated to the
requisite temperature within an oven by means of a suitable furnace, which
oven is constructed so as to operate on the principle herein made known,
being provided with the means of ascertaining and regulating the temperature,
substantially as described.
In witness whereof, I, the said Alfred Vincent Newton, have hereunto
set my hand and seal, this Twenty-third day of March, in the year
of our Lord One thousand eight hundred and forty-seven.