IMPROVEMENTS IN STAMPING AND SHAPING SHEET METAL
Year: 1846

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
FOXALL GRIFFITHS, of Birmingham, 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 Third day of February, in the ninth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
Thomas Foxall Griffiths, my exors, admors, and assigns, Her especial licence,
full power, sole privilege and authority, that I, the said Thomas Foxall
Griffiths, my exors, admors, and assigns, or such others as I, the said Thomas
Foxall Griffiths, my exors, admors, 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 expressed, should and lawfully might make, use, exercise, and vend,
within England, Wales, and the Town of Berwick-upon-Tweed, my Invention
of "IMPROVEMENTS IN STAMPING AND SHAPING SHEET METAL;" in which said
Letters Patent there is contained a proviso that I, the said Thomas Foxall
Griffiths, shall cause a particular description of the nature of my said Inven-
tion, and in what manner the same is to be performed, to be inrolled in
Her said Majesty's High 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 bad, will more fully and at
large appear.

page_text: 2
NOW KNOW YE, that in compliance with the said proviso, I, the said
Thomas Foxall Griffiths, do hereby declare that the nature of my said Invention,
and the manner in which the same is to be performed, are fully described
and ascertained in and by the following statement thereof, reference being had
to the Drawings hereunto annexed, and to the figures and letters marked
thereon, that is to say:-
My Invention relates to improvements in raising sheet metal, when the
processes of stamping and burnishing to form are resoted to for shaping sheet
metal. Heretofore sheet metal has been raised by the simple act of stamping
in dies, by raising and letting fall a succession of forcers, and the process of
burnishing to form has been combined with the ordinary process of stamping,
whereby sheet metal having been raised as far as possible in dies by the
process of stamping, the shaping has been completed by the process of bur-
nishing the stamped articles on chucks in a lathe; and to secure such last-
mentioned combined processes Letters Patent were granted to me the
Fifteenth day of February, One thousand eight hundred and thirty-four.
Now, my present Invention consists,
First, of an improvement in the form of the dies used when shaping sheet
metal by stamping in dies, by which the sheet metal at the sides of the vessel
or article produced will not be rendered more and more thin, according to
the greater extent to which the raising process may be carried, but the metal
in all parts will more nearly retain the thickness of the original sheet metal
from which the vessel or article is raised by stamping.
Secondly, my Invention consists of so combining the processes of shaping
sheet metal by burnishing, and shaping by stamping, that the process of
stamping is performed after as well as before burnishing to shape; and,
Thirdly, my Invention consists of applying a peculiar process of annealing
to sheet iron when stamping and burnishing to form, by which those processes
will be materially facilitated.
And in order that my Invention may be most fully understood and readily
carried into effect, I will proceed to describe the means pursued by me. A
great variety of articles, it is well known, are now made by stamping and
also by stamping combined with burnishing to form; and both of these
processes are well known; it will not therefore be necessary to enter into a
description of my Invention as applied to many articles, but it will be
sufficient to make choice of an instance where the raising is to a con-
siderable extent, as by so doing the nature and manner of performing my
Invention will be readily understood by a workman, and he will only have
to vary his dies, forcers, and chucks in order to make articles of other sizes

page_text: and forms according to my Invention. In shaping sheet metal by stamping,
as heretofore practised, the sides of the articles depend materially for the
height of the raising on the stretching or extending of the metal, and to this end
the metal at the outer circumference is supported throughout the processes of
stamping by a projecting flanch, which rests horizontally on the upper surface of
the die, such flanch being progressively reduced, and the metal thereof stretched
or extended, so that from the bottom to the upper edge the thickness of the
metal is brought thinner and thinner, which is objectionble; at the same
time, owing to the severe treatment to which the sheet metal is thus subjected,
it requires to be more often annealed in order to prevent its suffering injury
by the successive processes of stamping. And such is the extent to which
the metal is stretched or extended by raising according to the old practise,
that the disc or blank of metal employed for raising a vessel of a few inches
diameter to a considerable extent is only about three quarters of an inch
larger in diameter than the finished vessel raised therefrom by stamping;
whereas, according to my Invention, the blank or disc of sheet metal used
for making any particular article when the sides thereof are nearly upright
is of a diameter of about the diameter of the vessel or article added to the
depth of the vessel. Thus, supposing the raised vessel or article produced by
stamping in a die be six inches in diameter and three inches deep, then the
disc or blank of sheet metal would be about nine inches diameter; and if
the article when stamped therefrom be cut through the sides and bottoms,
all parts of it would be found of as nearly as may be the same thickness, and
that thickness the thickness of the original sheet metal. And such process
of raising by stamping will be found to be carried out more advantageously
than when working according to the old plan; for not only may articles be
raised to a greater depth without liability to injury of the metal, but the
annealing process will not be required to be so often performed.
Figure 1 shews the section of a die made according to the first part of my
Invention, a, a, being the upper bearing surface (which is small when com-
pared with the former practise), which first supports the outer edge or outer
circumference of the blank or disc of sheet metal, and by a succession of
forcers (made and used in the ordinary manner, as is well understood), the
article is progressively raised into the forms A, B, C, and thus far the raising
is similar to ordinary stamping of sheet metal in dies; but the old raising
process, which depends on there remaining at all times a flanch on the upper
-surface of the die, cannot be continued, as nearly the whole of the metal has
been forced into the die, and there remains but little flanch to support the
outer edge. The novel character of the die, Figure 1, now comes into action;

page_text: the metal which has been stamped has at the sides assumed a conical form,
corresponding with the figure of the upper part of the die between the points
of bearing at a, a, and the points of bearing b, b, and it is the employment
of dies with such second points of bearing at b, b, which constitutes the
peculiarity of this part of the Invention. A further series of forcers are now
to be employed to produce the article successively into the forms D, E, F,
and G, the portion of the die between a and b acting as a die through which
the metal is drawn, and this causes the metal progressively to be reduced in
diameter at the upper part of the article, this being effected by the successive
pressures of the forcers on the lower part of the article, for the upper or
conical portion of metal is not touched by the forcers. In producing the
article G, it will be seen that seven forcers are used in the die Figure 1;
but it should be stated that the number of forcers will vary according to
the nature of the metal and of the articles to be produced. The article G is
supposed to be made of the best charcoal iron plate, which, when the raising
is considerable, offers the greatest difficulty of any sheet metal; but a workman
accustomed to stamping metals will readily judge of how far he may raise a
particular sheet metal by each succeeding forcer. I have only thought it neces-
sary to show a die for making articles from circular blanks or discs of sheet
metal, but dies according to this part of my Invention may also be made,
suitable for stamping articles from oval or oblong blanks of sheet metal. The
article above described having been raised as far as may be by stamping, is,
when carrying out the second part of my Invention, to be placed on chuck
Figure 2, which I make of cast or of the best wrought iron, and on this chuck
the article is burnished so as to fit the chuck, the article being borne up to the
chuck by a back centre, as is now well understood when burnishing to form
(by using strong heavy burnishers) is practised in contradistinction to burnishing
simply to polish. By this means the article H is produced, which is to undergo
a further process of raising by stamping in a die, such as is shown in section at
Figure 3, the forcer not touching at the sides but only at bottom, by which
the article is rendered into the form I, when it is to undergo a further process
of burnishing to form or shape on the chuch Figure 4, which will render the
article into the form J, and then again it is to undergo a further process of
raising by stamping in the die Figure 5, the forcer not touching the sides but
only the bottom of the article, by which the article K will be produced, which
is to be burnished into form on the chuck Figure 6, by which the article L will
be produced. And in this manner, by repeating the processes of raising by stamp-
ing, interposing (from time to time) the process of burnishing to form on suitable
chucks, sheet metal may be raised to a much greater extent, with less liability

page_text: to injure the metal than heretofore, and the workman will vary the shape and
depth of his dies, and the chucks used by him, according to the nature of the
article to be made. If it be desired to form the article L into a fluted shape,
then I carry on the stamping process still further by using a die such as at
Figure 7 with a forcer which only fits the lower part of the die, the upper part
of the forcer not touching the article when forced into it, by which the article
will be rendered into the shape M. And in order to make a finished article I
employ a die Figure 8, with a forcer suitable for touching the article at all
parts, so as to force all parts thereof into the shape of the die, excepting just
at the centre of the bottom of the article, where the die is cut away in order to
allow of a ram to ascend to force the article out of the die, as is shown. It
is well known that in stamping and burnishing metals, when those processes
are carried on to shape articles out of sheet metal, the metal hardens, and the
same requires to be annealed from time to time in order to soften the same,
that it may safely undergo further stages of the processes.
I have not, in the above description of the first and second parts of my
Invention, thought it desirable to speak of the annealing (where that process
is required) to which the sheet metal employed may from time to time require
to be subjected, as that will depend on the nature of the metal, and therefore
the repetition of the process of annealing from time to time, in carrying out this
Invention, is, as heretofore, to be left to the judgment of the workman. At the
same time, as part of my Invention relates to the manner of annealing when
operating on sheet iron by stamping, or by stamping combined with burnishing
to form, I will proceed to explain how this part of my Invention is to be
carried into practice.
Heretofore, when annealing sheet metal from time to time as it undergoes
'the processes of stamping and burnishing to form, it has been usual to intro-
duce the articles in various stages of their manufacture into a furnace called a
muffle, and having heated the articles to a proper extent, as is well understood,
the same are allowed to cool down, and I have found that by such means of
annealing the surfaces, when of iron, are very liable to have scales produced
thereon, which are not only injurious in reducing the thickness of the sheet
metal, but the same injures the dies, and it is very difficult to get the burnisher
to touch such surfaces of iron. I have discovered that, by applying a peculiar
process of annealing (similar to that used when annealing articles made of
malleable cast iron) to sheet iron from time to time between the processes
of stamping and burnishing to form, I am enabled to avoid producing scale on
the surfaces of iron; and the iron coming from such process of annealing will

page_text: be not only more soft and suitable to undergo further stamping, but the
burnishing tools will act more readily thereon. Articles of sheet iron requiring
to be annealed before going through further processes of stamping, or before
undergoing the process of burnishing to form, are to be packed into vessels
such as are used when annealing articles cast from malleable cast iron, and the
interstices are to be filled up with the dust of Cumberland iron ore, and this
dust is mixed with the dust of coke or with fine sand, and the vessels are to
be closed with an iron cover, and luted as heretofore. It should however be
stated, that I prefer the ore, for the purpose of annealing articles according
to my Invention, to have been first used by the annealer in annealing articles
of malleable cast iron in preference to using fresh ore. The quantity of the
ore I use is about one part to eight parts of coke or of sand. The articles
being thus packed in vessels, and well covered with the materials above
mentioned, are then to be heated in a suitable oven to a good blood-red by
daylight, which takes about twelve hours, when the whole is to be allowed
to cool.
I would remark, that I do not claim the annealing process above mentioned
when uncombined with the shaping of sheet metal by stamping, or by stamping
.and burnishing to form.
Having thus described the nature of my Invention, and the manner in which
the same is to be performed, I would state that the details may be varied so
long as the peculiar character of either part of my Invention be retained; and
I would have it understood that what I claim is,-
First, the mode of shaping sheet metal by stamping, by employing dies such
as are shown and described in respect to Figure 1.
Secondly, I claim the so combining the processes of stamping and burnishing
sheet metal, in order to shape the same, that the stamping process is caused to
be applied after as well as before the process of burnishing to form, as herein
described. And,
Thirdly, I claim the application of the annealing. process herein described
when stamping, and when stamping and burnishing sheet iron in order to
shape the same.
In witness whereof, I, the said Thomas Foxall Griffiths, have hereunto
set my hand and seal, this Twenty-fourth day of July, in the year of
our Lord One thousand eight hundred and forty-six.
THOMAS FOXALL (L.s.) GRIFFITHS.

page_text: AND BE IT REMEMBERED, that on the Twenty-fourth day of July, in
the year of our Lord 1846, the aforesaid Thomas Foxall Griffiths came before
our said Lady the Queen in Her Chancery, and acknowledged the Specifi-
cation aforesaid, and all and every thing therein contained and specified, in
form above written. And also the Specification aforesaid was stamped
according to the tenor of the Statute made for that purpose.
AND BE IT REMEMBERED, that on the Twenty-fourth day of July, in
the year of our Lord 1846, the aforesaid Thomas Foxall Griffiths came before
our said Lady the Queen in Her Chancery, and acknowledged the Specifi-
cation aforesaid, and all and every thing therein contained and specified, in
form above written. And also the Specification aforesaid was stamped
according to the tenor of the Statute made for that purpose.
Enrolled the Thirtieth day of July, in the year of our Lord One
thousand eight hundred and forty-six.