IMPROVE- MENTS IN BRONZE ORDNANCE
Year: 1869

page_text: LETTERS PATENT to William Robert Lake, of the "International
Patent Office," No. 8, Southampton Buildings, Chancery Lane,
London, Consulting Engineer, for the Invention of "IMPROVE-
MENTS IN BRONZE ORDNANCE."-A communication from abroad by
Samuel Buel Dean, of Boston, Massachusetts, United States of
America.
Sealed the 2nd July 1869, and dated the 10th May 1869.
5
COMPLETE SPECIFICATION filed by the said William Robert Lake
at the Office of the Commissioners of Patents, with his Petition and
Declaration, on the 10th May 1869, pursuant to the 9th Section
of the Patent Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
ROBERT LAKE, of the "International Patent Office," No. 8, Southampton
Buildings, Chancery Lane, London, Consulting Engineer, send greeting.
WHEREAS I am in possession of an Invention for "IMPROVEMENTS IN
BRONZE ORDNANCE," and have petitioned Her Majesty to grant unto me,

page_text: my executors, administrators, and assigns, Her Royal Letters Patent
for the same, and have made solemn Declaration that it has been
communicated to me from abroad by Samuel Buel Dean, of Boston,
Massachusetts, United States of America.
NOW KNOW YE, that I, the said William Robert Lake, do hereby
declare that the following Complete Specification, under my hand and
seal, fully describes and ascertains the nature of the said Invention, and
in what manner the same is to be performed, in and by the following
statement, reference being had to the accompanying Drawing forming
a part of this Specification:
It is very desirable in pieces of bronze ordnance, especially in bronze
field pieces and boat guns, to produce a degree of hardness, smoothness,
and accuracy of bore which has not hitherto been attained by the ordinary
process of boring and reaming. Even in the best bronze guns as
heretofore made there are always defects in the bore of a greater or less
extent caused by the porosity of the metal arising from coarse crystal-
lization of the bronze in cooling. Slight cavities are also sometimes
increased by the action of the boring tool in tearing out comparatively
loose particles of the metal; these defects are agravated in the service
of the gun by the action of the powder gases consequent upon explosion
of the charges. Lack of sufficient hardness of the bore of bronze guns
gives rise to permanent enlargement of the bore at the seat of the charge
where the gaseous pressure is greatest, and as the bore becomes enlarged
the projectiles have increased windage, and often bound and rebound,
first forming an indentation or elliptical cavity at the seat of the shot,
and then rebound and strike the bore on the upper side, and sometimes
again upon the bottom before leaving the gun, forming indentations at
the points of impact.
By my Invention I improve the quality of guns made of bronze in
that I harden, condense, and smooth the metal surrounding the bore
rendering the bore of uniform size and lessening its minor depressions
and porosity. I effect this condensation substantially in the following
manner: If a bronze gun is to be treated I bore and ream the rough
casting carefully to secure the best bore possible by such means, of a
diameter about one-eighth of an inch less than it is to be when finished.
At this time the bore is inspected, and if found free from such defects as
would cause the rejection of the piece by ordnance officers, it is ready
to be prepared for treatment in accordance with my Invention. The

page_text: rough gun casting is then to be enclosed in such hoops or flask as will
constitute a strong casing; but as the exterior of the casting is rough
and irregular, as is also the interior of the casing, I propose to leave
between the gun casting and the casing an annular space to be filled
with cement or other suitable cheap material, which will make a hard
unyielding filling. It may however be preferable to rough turn the
gun body and to bore out a casing to fit upon the body, which casing
may be made in halves provided with flanges, by which the said casing
is secured and clasped upon the gun. The encased gun is then to be
placed in a frame or upon a bed somewhat like a boring mill for guns,
but instead of using a bar provided with cutters I fix in the end of the
bar a smooth cylindrical plug of hardened steel about five hundredth's
of an inch larger than the diameter of the reamed hole in the gun. The
plug should be made of two frustums of cones with their bases con-
nected by a short cylinder.
For condensing the bores of rifled guns the plugs used should have
ribs to correspond with the grooves previously made by a rifling machine.
The bore being well lubricated the steel plug is made to traverse the
bore by a screw or other suitable mechanical means till it reaches the
bottom of the bore, proper provison being made to allow air and excess
of the lubricant to escape through a vent in the plug or at the bottom
of the bore. Instead of forcing a plug or plugs from the muzzle to the
bottom of the bore the condensation may be performed by commencing
at the bottom of the bore and drawing the plug outward, in which case
the plugs should be so made as to be expansible. In breech-loading
guns the condensation may be effected by forcing the plugs from the
breech to the muzzle. After the first plug has been removed from the
bore two or more similar plugs are to be successively forced through,
enlarging the bore to the desired size. Care should be taken that each
succeeding plug shall have a diameter slightly larger than the one which
preceded it, and each plug should perform a slightly smaller amount of
compression than its preceding plug, on account of the increasing
hardness and density of the bore, which increases the resistance to be
overcome by each successive plug. The bottom of the bore may be
treated to produce a similar condition of the metal, either by powerful
compression exerted upon the metal, or by blows upon a set or former
adapted to the shape of the bottom of the bore. During this operation
of condensing the metal of the gun a considerable strain may be exerted

page_text: upon the encasing hoops or flask and will be resisted thereby, thus
insuring the gun against an injurious expansion of its walls. The gun
thus condensed will of course have the densest hardest metal upon the
interior surface, and the density and hardness will rapidly diminish in an
outward direction. Whatever tangential strain is created will be within
the limits of the elasticity of the metal, since it is rigidly held by the
hoops or casing against undue expansion; when this condensation is
properly effected it will materially increase the strength and durability of
a gun, not only because of the increase of the density of the metal imme-
diately surrounding the bore, hut because also of the increased hardness
of the bore, bardness being a quality greatly desired and prized in bronze
guns, and never heretofore found in such metal to the desired extent.
Its inferiority in hardness to steel has caused the substitution of steel to
a considerable extent, particularly for rifled field guns. By carefully
conducted experiments I have proved that the hardness and the tensile
strength of the metal are increased by the condensation described. In
condensing the material surrounding the bore I accomplish regularly
and beneficially what is irregularly and injuriously effected in detached
places during the ordinary extended service of a gun by pressure of the
powder gases and the balloting of the shot. By condensation of the
metal substantially to the extent and by the means described, I do not
impair the strength of the exterior metal, but put it in such relation to
the inner condensed part as to secure the greatest combined usefulness
in resisting rupture. The benefit derived from casting and cooling guns,
according to the plan now known as that of "Rodman," I impart to
bronze guns by my process of finishing the bore, together with the
quality of hardness at the surface of the bore, and a degree of smoothness
hitherto unequalled, all of which add to the efficiency and durability of
guns made as I have described over guns simply bored and reamed.
The accompanying Drawing shows the two methods of encasing a gun
previous to its being treated as before described, to enlarge the bore by
condensing the metal near the boundaries thereof,
Figure 1 is a sectional view of a gun encased by the employment of a
älling between its exterior and the interior of the casing.
Figure 2 is a view similar to Figure 1, showing the gun casting as
turned, and the casing as bored to fit the turning.
Figure 3 shows an outside elevation of the gun casing or flask, which
may be made in sections joining at the lines, .

page_text: Figure 4 is a cross section of the gun case, the rough gun body and
the filling between them taken in a plane passing through the axial line
of the gun trunions.
Figure 5 is a view similar to Figure 4, except that the interior of the
case is bored and the exterior of the gun is turned, so that contact of
the gun with the oase is obtained.
In Figure 2 the dotted lines show an approximation to the form to
which the rough gun body is to be finished after the condensation of the
metal surrounding the bore is completed.
In Figures 1, 2, 4, and 5, the metal surrounding the bore is more
deeply shaded than the rest of the metal of the gun, and this may be
considered as a representation of the condition of the condensed
boundary metal of the bore, the lighter colored metal being that which
is not sensibly affected by the condensation.
In treating a rifled gun to produce the desired condition of the metal
around the bore the plain or smooth bore may be first condensed, as
before described, then the smooth bore thus improved may be rifled, and
the bottoms and sides of the rifle grooves may be smoothed, hardened,
and condensed by forcing through the rifled bore ribbed plugs of
hardened steel suitably formed to produce the condensation required.
Having thus fully described the said Invention, as communicated to
me by my foreign correspondent, and shewn how the same may be con-
veniently and advantageously carried into practice, I claim, a bronze
gun, in which the metal immediately surrounding the bore is put in the
condition that is produced by the process of condensation herein set
forth.
In witness whereof, I, the said William Robert Lake, have hercunto
set my hand and scal, this Tenth day of May, in the year of
WILLIAM ROBERT LAKE. (L.S.)