An Improved Method of and Apparatus for Hardening or Tempering Projectiles or Shells:
Year: 1888

page_text: PROVISIONAL SPECIFICATION.
An Improved Method of and Apparatus for Hardening or Tempering
Projectiles or Shells:
We ROBERT LOW, of the Royal Laboratory, Woolwich Arsenal, in the County of
Kent, Engineer, and HENRY HERON SMITH, of Wilton House, Vicarage Park,
Plumstead in the County of Kent, Metallurgical Chemist, do hereby declare the
nature of this invention to be as follows:-
Our invention relates to the hardening or tempering of projectiles or shells and
comprises an improved method and apparatus hereinafter described.
According to our improved method of hardening or tempering, we provide for
extracting the heat from the projectile or shell in a more gradual manner than is
practicable by the ordinary method of plunging or immersing the projectile or shell
in oil or other. liquid. For this purpose we place the projectile or shell in a case or
envelope before immersing it in the liquid. This case or envelope obstructs, moderates
or retards the transmission of heat from the projectile or shell to the liquid outside
the said case or envelope.
In hardening or tempering a projectile or shell according to our said invention, the
said projectile or shell is heated to a suitable temperature and is placed, preferably in
a vertical position with its conical or conoidal end or head downward, in a metallic
case or envelope, the internal shape or configuration of which should correspond to
the external shape or configuration of the head of the projectile and which should
completely cover the said head, projecting some distance beyond the shoulder; we
prefer that the case or envelope should be of less substance or thickness in the vicinity
of the shoulder than in that of the point of the projectile or shell. This metallic case
or receptacle with the projectile or shell therein is immersed, or partially immersed in
water, oil or other liquid, which is preferably caused to flow continuously through the
tank or other receptacle in which the hardening is effected. The said case or envelope
conducts the heat from the projectile or shell to the liquid in which it is immersed
and thus extracts the heat from the projectile more gradually than is practicable by

page_text: direct immersion of the projectile in the liquid, and, by virtue of the varying
substance or thickness of the metai, the heat is transmitted with greater rapidity from
the thicker or more massive portions of the head, than from the point; consequently
the state of tension which is inevitably set up in a projectile when hardened by direct
contact with the liquid is obviated.
The said case or envelope is preferably made with a flat base or otherwise so that it
can stand upon a suitable bracket or support in the tank containing the water or
other liquid. It is usually provided with bolts or studs upon which is firmly secured
a cross-bar having passed through the same a screw, whereby pressure may be applied
to the projectile or shell to keep the surface thereof in close contact with the interior
surface of the said case. Other means may, however, be used for this purpose; or the
projectile may be held in contact with the case simply by its own weight.
Dated this 22nd day of March 1888

page_text: An Improved Method of and Apparatus for Hardening or Tempering
Projectiles or Shells. .
We, ROBERT Low, of the Royal Laboratory, Woolwich Arsenal, in the County of
Kent, Engineer, and HENRY HERON SMITH, of Wilton House, Vicarage Park,
Plumstead, in the County of Kent, Metallurgical Chemist, do hereby declare the
naturo of this invention and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement :-
Our invention relates to the hardening or tempering of projectiles or shells and
comprises an improved method and apparatus hereinafter described.
According to our improved method of hardening or tempering, we provide for
extracting the heat from the projectile or shell more slowly or gradually than is
practicable by the ordinary method of plunging or immersing the projectile or shell
directly in oil or other liquid. For this purpose, we place the projectile or shell,
before immersing it in the oil or other cooling medium, in a case or envelope of metal
or other suitable material, which, being interposed between the projectile and the oil
or other liquid, obstructs, moderates or retards the transmission of heat from the said
projectile to the oil or other liquid outside the said case or envelope.
In hardening or tempering a projectile or shell according to our said invention, the
said projectile or shell is heated to a suitable temperature and is placed, preferably in
a vertical position with its conical, conoidal or ogival end or head downward, in a
metal or other case, envelope or receptacle, the internal shape or configuration of
which should correspond to the external shape or configuration of the head of the
projectile, and which should completely cover the head and project some distance
beyond the shoulder of the projectile. We prefer that the caso or envelope should be
of less substance or thickness at the part which comes in contact with the shoulder of
the projectile or shell, than at that which comes in contact with the point thereof.
The case or receptacle with the projectile or shell therein is immersed or partially
immersed in water, oil, or other cooling medium, which is preferably caused to flow
continuously through the tank or other receptacle in which the hardening or tempering
is effected. The said case or envelope conducts the heat from the projectile or shell
to the liquid in which it is immersed and thus extracts the heat from the projectile or
shell more slowly or gradually than is practicable by direct immersion of the pro-
jectile or shell in the liquid, and, by virtue of the varying thickness of the metal of
the case or envelope, the heat is transmitted with greater rapidity from the thicker or
more massive portions of the head than from the point; the state of tension which is
inevitably set up in a projectile when hardened by direct contact with the liquid is
thus obviated. The said case or envelope is preferably made with a flat base or in
any other convenient manner so that it can stand upon a suitable bracket or support
in the tank containing the water or other liquid. It is usually provided with suitable
means whereby pressure may be applied to the projectile or shell to keep the surface
thereof in close contact with the interior surface of the said case or envelope; or
the projectile or shell may, if desired, be retained in contact with the case merely by
its own weight.
In the accompanying drawing we have shown, in vertical section, one form of our
apparatus for hardening or tempering projectiles or shells.
A indicates the projectile or shell to be hardened; B is the tank for containing the
oil or other cooling medium.

page_text: a is an envelope or case which is constructed of metal of varying thickness, being
thinner at the part a¹ than at the part a² and which has a flat base a³ to rest upon a
stand or bracket in the tank B. The projectile A is shown inserted in the case or
envelope a, the internal configuration of which corresponds, as above stated, to that
of the outer surface of the shell, so as to ensure contact of the exterior surface of the
shell with the interior surface of the said case or envelope. To more effectually ensure
close contact of the said surfaces, we provide a screw-spindle b which is passed through
a tapped hole in a cross-bar c secured in any convenient manner upon pillars or
studs d, d fixed in the case or envelope a. This screw-spindle is provided with a
flanged disc or head e, in which it is free to turn and which fits into and bears against
the base of the projectile. The said screw-spindle is, moreover, provided with a hand-
wheel bor other suitable device for operating it.
The cross-bar c is hinged or pivoted on the pillar or stud d and is adapted to engage
with the pillar or stud d in such a manner that, when the dise or head e is withdrawn
from a projectile by rotating the screw-spindle b, the said cross-bar can be turned
upon or about the pillar or stud d to permit the removal of the hardened pro-
jectile from the case a and the introduction therein of another projectile to be
hardened.
In hardening a projectile by means of the apparatus shown in the drawing, the
said projectile is first heated to any required temperature and is then placed in the
case or envelope a; the cross-bar c is then moved into its operative position, and, by
turning the screw b, the projectile is forced into intimate contact with the interior of
the case or envelope a. The said case or envelope with the projectile therein is then
partially immersed in the oil or other cooling medium in the tank B and placed upon
the support C, where it is allowed to remain for the required length of time to effect
the hardening or tempering of the projectile. The oil or other liquid is preferably
caused to flow continuously through the tank B.
Other means than those above described may be employed for forcibly pressing the
projectile into the case or envelope; or the mere weight of the projectile may, in
some cases, be sufficient for this purpose without the application of pressure.
Moreover it is obvious that we can, if desired, use for the purpose of our invention
a case or envelope of uniform thickness throughout.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed we wish it understood that
we claim :-
J
First. In the hardening or tempering of projectiles or shells, the employment of a
metal or other case or envelope of uniform or of varying thickness interposed between
the projectile or shell and the oil or other cooling medium, for the purpose above
specified.
Second. The iniproved method of hardening or tempering a projectile or shell,
consisting in first heating the same, then placing it in a case or envelope of metal or
other suitable material and subjecting it to end wise pressure to bring its surface into
· close contact with that of the said case or envelope, and then immersing the said case
or envelope with the projectile therein in oil or other cooling medium, substantially as
set forth.
Third. The improved apparatus comprising the case or envelope and the screw-
spindle for forcibly pressing the projectile or shell into the same, substantially as
described with reference to the accompanying drawing, for the purpose specified.
Date this 21st day of Dasanilion 1000
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London,
Agents for the Applicants.