IMPROVEMENTS IN THE MANUFACTURE OF CAST IRON BULLETS, AND IN THE APPARATUS EMPLOYED THEREFOR."
Year: 1880

page_text: LETTERS PATENT to Thorsten Nordenfelt, of Saint Swithin's Lano, in the
City of London, Civil Engineer, for an Invention of " IMPROVEMENTS IN THE
MANUFACTURE OF CAST IRON BULLETS, AND IN THE APPARATUS EMPLOYED
THEREFOR."
PROVISIONAL SPECIFICATION left by the said Thorsten Nordenfelt at
the Office of the Commissioners of Patents on the 12th May 1880.
"
THORSTEN NORDENFELT, of Saint Swithin's Lane, in the City of London, Civil
Engineer. IMPROVEMENTS IN THE MANUFACTURE OF CAST IRON BULLETS, AND
IN THE APPARATUS EMPLOYED THEREFOR."
The object of my Invention is to make cheap bullets for such calibres where lead
bullets would become too large by such a method and of such a quality that they
are equally good to steel bullets with regard to accuracy in firing, and therefore
can be used with advantage especially for practising.
These bullets are made of chilled cast iron, the diameter being slightly smaller
than the calibre of the gun they are intended for, and, on the middle, or where
the bullets commence curving towards the point, they have one or more rings of
copper or other suitable material projecting from the iron, so much that they fill
the bore of the barrel, but without taking the rifle grooves, and thus protect the
rifling and give the guidance to the bullets without causing the bullet to rotate.
At the rear end is a gas check shaped somewhat like a cup with a hole through
the bottom, and so placed that the powder gas pressed in between the bullet and
the gas check widens it out and makes it fill the rifling, which stops the escape of
gas and gives the bullet its rotation.
For making these bullets I use chills made in two halves and with a plug against
the base of the bullet. The chills are provided with grooves to receive the copper
disks, which are made with a regular or irregular polygonic holo through the
middle, so large that it just gives sufficient stuff for the iron to grip on; the outer
diameters of the disks are left large enough for the machining which is to be done
afterwards. Besides these grooves for the guiding disks there is a space or groove
for the gas check at the rear end in the mould, and the gas check, which has a hole
Duise G

page_text: similar to that in the disks, is placed here with the widest end backwards, and held
in position by means of the plug before mentioned. This plug may have a head
with notches sloping in horizontal and vertical directions in which hooks fixed on
the chill grip, so that with a half or a quarter turn the plug is fastened and keeps
the gas check firm; this last operation is done after the two half chills are put
together, but the fixing of the gas check may also be done by other convenient
arrangements.
When the above is performed the chill is ready to receive the molten iron, which
generally is poured in from the side at such a temperature as not to melt the
copper, or at the utmost only melt the inside edges of the polygonic holes, which
are then held tightly by the iron and help to fasten the disks and the gas check to
the bullet. When the bullet is taken out of the chill the point, which is cast full,
is if required ground sharp, and all irregular projections ground off on a grindstone
or emery wheel. Thereafter the disks are squeezed down or turned off in a suitable
machine to form rings and make these the required size. Lastly, the bullet is
drawn through a die for sizing the gas check and making this concentric with the
bullet.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Thorsten Nordenfelt in the Great Seal Patent Office on the
11th November 1880.
THORSTEN NORDENFELT, of Saint Swithin's Lane, in the City of London, Civil
Engineer. "IMPROVEMENTS IN THE MANUFACTURE OF CAST IRON BULLETS, AND
IN THE APPARATUS EMPLOYED THEREFOR."
My object is to make cheap bullets by such a method and of a quality that they
are equally good to steel bullets with regard to accuracy in firing, and therefore can
be used with advantage for practising in firing.
These bullets are made of chilled cast iron, the diameter being slightly smaller
than the calibre of the gun they are intended for. On the middle, or where the
bullets commence curving towards the point, there are one or more rings of copper
or other suitable material, which projects from the iron so much that they fill the
bore of the barrel, and thus protect the firing and give the guidance to the bullets
in the same way as the rings used some times on steel bullets. At the rear end is
a gas check shaped somewhat like a cup with a hole through the bottom, and so
placed that the powder gas pressed in between the bullet and the gas check widens
this out and makes it fill up the rifling, which stops the escape of gas and gives the
bullet its rotation.
For making these bullets I use chills each made in two halves and with a loose
plug against the base of the bullet. The chills are provided with grooves to receive
the copper discs, which are made with a regular or irregular polygonic hole through
the middle, so large that it just gives sufficient stuff for the iron to grip on; the
outer diameter of the discs are left large enough for the machining which is to be
done afterwards.
Besides these grooves for the guiding discs there is made a space for the gas
check at the rear end of the bullet, and the gas check, which has a hole similar to
that in the discs, is fastened here with the widest end backwards by means of the
loose plug before mentioned; this plug has a head which may be made with
notches sloping in horizontal and vertical directions in which books fixed on the
chill grip, so that with half or quarter turn the plug is fastened and keeps the gas
check firm; this last operation is done after the two half chills are put together,
but may also be done by some other convenient arrangement. When the above is
performed the chill is ready to receive the molten iron, which generally is poured in
from the side at such a temperature as not to melt the copper, or in the utmost
only melt the inside edges of the polygonic holes, which then amalgamate with the
iron and help to fasten the discs and gas check to the bullet. When the bullet is
taken out the point, which is cast full, is ground sharp, and all irregular projections
ground off on a grindstone or emery wheel. Thereafter the discs are squeezed
down in a suitable machine to form the rings and make them to the required size.
Lastly, the bullet is drawn through a die for sizing the gas check and making this
concentric with the bullet.
In order that the said Invention may be most fully understood and readily
carried into effect, I will proceed to describe the Drawings hereunto annexed.

page_text: Figure 4 represents a longitudinal section of one of the bullets as it leaves the
mould, and Figure 5 is a similar view of the finished bullet.
In Figure 1, a, a, are the cavities in which the bullets are cast, and which
correspond in form to them; a¹, a¹, are grooves in these cavities to receive the
guide rings, marked b in Figures 4 and 5; a", a¹¹, are similar grooves to receive
the base cups or gas checks, marked c in Figures 4 and 5; d, d, are grooves in the
chill blocks forming the runner with its branches; e, e, are pins which project from
the face of the chill block represented in Figure 1, and are received into corresponding
holes in the other chill block. f, f, are plugs, by which the base ends of the cavities
a, a, are closed for casting. These plugs have inclines upon their outer ends, which
when the plugs are in place are made to engage with lugs fixed to the chill blocks.
The plugs, have convex faces corresponding in form to the base of the bullet.
The guide ring b and the base cup c are both by preference made from sheet copper,
which in the case of the base cup is first pressed in to form by well known methods.
These parts may be of brass in place of copper, but copper is very suitable, as it is
sufficiently soft not to injure the interior of the barrel, and its melting point is
sufficiently high to allow of iron being readily cast upon it, as described, if only
reasonable care and judgment be used. After leaving the moulds the bullets are
separated from the runners, and any irregularities are ground off on a stone or
emery wheel. By the same means the nose of the bullet, which is cast somewhat
full, as is indicated by Figure 4, is pointed, as it is seen in Figure 5. Finally, the
ring b is flattened by pressure, and it and the base cup c are finished by forcing the
bullet through a die.
Having thus described the nature of my said Invention, and the manner of
performing the same, I would have it understood that I claim, my method of and
apparatus for the manufacture of cast iron bullets, and especially combining the
guide ring and the base cup, or either of them, with the bullet by placing them in
the chills and casting the iron upon them, substantially as herein described.
In witness whereof, I, the said Thorsten Nordenfelt, have hereunto set my
hand and seal, this Second day of November, in the year of our Lord
One thousand eight hundred and eighty.