IMPROVE- MENTS IN SCREW PROPELLERS AND, IN THE SHAFTS AND CRANKS BY WHICH THEY ARE DRIVEN,, WHICH IMPROVEMENTS ARE ALSO APPLICABLE GENERALLY TO THE SHAFTS AND CRANKS OF MARINE, STATIONARY, AND LOCOMOTIVE STEAM ENGINES
Year: 1855

page_text: LETTERS PATENT to Henry Bessemer, of Queen Street Place, New Cannon
Street, in the City of London, Engineer, for the Invention of "IMPROVE-
MENTS IN SCREW PROPELLERS AND, IN THE SHAFTS AND CRANKS BY WHICH THEY
ARE DRIVEN,, WHICH IMPROVEMENTS ARE ALSO APPLICABLE GENERALLY TO THE
SHAFTS AND CRANKS OF MARINE, STATIONARY, AND LOCOMOTIVE STEAM
ENGINES."
⋅
PROVISIONAL SPECIFICATION left by the, said Henry Bessemer at the
Office of the Commissioners of Patents, with his Petition, on the 18th
June 1855..
I, HENRY BESSEMER, of Queen Street Place, New Cannon. Street, in the
County of Middlesex, Engineer, do hereby declare the nature of my Invention
for "IMPROVEMENTS IN SCREW PROPELLERS AND IN THE SHAFTS AND CRANKS BY
WHICH THEY ARE DRIVEN, WHICH IMPROVEMENTS ARE ALSO APPLICABLE GENERALLY
TO THE SHAFTS AND CRANKS OF MARINE, STATIONARY, AND LOCOMOTIVE STEAM
ENGINES," to be as follows:
The powerful strains. to which screw propellers and their shafts and cranks
are subjected renders it necessary that great strength should be given to those
parts of marine-machinery; this great strength is attained at present only
by making the aforesaid parts both massive and heavy, which circumstance
not only entails a large extra cost in their manufacture, but is productive of

page_text: much friction and loss of power, while the great weight of metal at that part
of the vessel where these heavy masses are necessarily placed is very disad-
vantageous; this is particularly the case with the propeller, which, from the
difficulty of forging it in wrought iron of a proper form, and from other
circumstances, is often cast in gun metal, and consequently must be made to
deviate at certain parts from the desired form which otherwise would be
given to it, in order that a metal so easily bent may have the required degree
of strength, while at the same time its weight and cost are in like manner
increased.
Now, the object of my said Invention is to give to the propeller and its
shaft and crank the requisite degree of strength to enable them to withstand
the strains to which they are subjected with a very much less weight of metal
than is at present used, or in some cases to give a much greater strength to
the said parts of marine machinery without the necessity of making a corre-
sponding increase in the weight thereof, and also to diminish the cost of the
said parts of machinery. For this purpose I make suitable moulds of the said
propeller and of its shaft and crank, which moulds I prefer to be made in
loam and baked dry, in a manner well understood in the preparation of moulds
for articles made in cast iron, and into the moulds so prepared I pour or run
steel in a state of fusion, or I use in lieu thereof a mixture of steel and pig
or refined iron, which is somewhat less expensive. It will be observed that the
propeller, the shaft, or the crank so produced will be founded in steel, or a
mixture of steel and iron, the process of casting giving at once the general
form and proportion of each part thereof, in contradistinction to the process of
forging or hammering, by which articles in wrought iron and forged steel are
made. In the manufacture of very massive castings it will be found sufficient
to allow the metal to cool slowly in the mould in order that it may be soft
enough to be filed or turned, but where great toughness is required the casting
should be put into a suitable annealing oven, and there be kept at a red heat
for a period of time according to its thickness or the degree of toughness
required. In-consequence of the great cohesive force of steel and its power
to resist torsion as compared with wrought iron, I am enabled to make the
propeller and its shaft and crank of less weight and size than usual without
diminishing their strength, or advantage may be taken of the cohesive force
of steel to give greater stability to the work, keeping the size of the parts the
same as are at present used. It will be also understood that the manufacture
of cranks and shafts for marine steam engines by the process of founding in
steel, or a mixture of steel and iron, is also applicable to the manufacture of
cranks and shafts for stationary and locomotive steam engines. The melting

page_text: of the steel, or a mixture of steel and pig or refined iron, may be effected in
pots, as is at present practised in the melting of steel, for the purpose of pro-
ducing bars or rods of cast steel, in which case a large number of melting
pots will be required, and the workmen should as nearly as possible at the
same time pour the contents of the said pots into the mould, or into a channel
or channels leading thereto; but I prefer to melt steel, or a mixture of steel-
and iron, for the purposes of this Invention, by an improved mode or modes
of melting and. casting steel, or mixtures of steel and iron, as set forth in
Provisional Specification of a Patent for Improvements in the Manufacture of
Cast Steel, and Mixtures of Steel and Cast Iron, bearing even date herewith.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Henry Bessemer in the Great Seal Patent Office on the
18th December 1855.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HENRY
BESSEMER, of Queen Street Place, New Cannon Street, in the City of London,
Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Eighteenth day of June, in the year of our Lord One
thousand eight hundred and fifty-five, in the eighteenth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
Henry Bessemer, Her special licence that I, the said Henry Bessemer, my
executors, administrators; and assigns, or such others as I, the said Henry
Bessemer, my executors, administrators, and assigns, should at any time agree
with, and no others, from time to time and at all times thereafter during the
term therein expressed, should and lawfully might make, use, exercise, and
vend, within the United Kingdom of Great Britain and Ireland, the Channel
Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN SCREW PRO-
PELLERS AND IN THE SHAPTS AND CRANKS BY WHICH THEY ARE DRIVEN, WHICH
IMPROVEMENTS ARE ALSO APPLICABLE GENERALLY TO THE SHAFTS AND CRANKS OP
MARINE, STATIONARY, AND LOCOMOTIVE STEAM ENGINES," upon the condition
(amongst others) that I, the said Henry Bessemer, by an instrument in
writing under my hand and seal, should particularly describe and ascertain
the nature of the said Invention, and in what manner the same was to be
performed, and cause the same to be filed in the Great Seal Patent Office
within six calendar months next and immediately after the date of the said
Letters Patent..

page_text: .
NOW KNOW YE, that I, the said Henry Bessemer, do hereby declare the
nature of the said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement thereof (that is to say) :-
.:
The powerful strains to which screw.propellers and their shafts and cranks
are subjected renders it necessary that great strength should be given to those
parts of marine machinery. This great strength is attained at present only by
making the aforesaid parts both massive and heavy, which circumstance not
only entails a large extra cost in their manufacture, but is productive of much
friction and loss of power, while the great weight of metal at that part of the
vessel where these heavy masses are necessarily placed is very disadvantageous;
this is particularly the case with the propeller, which, from the difficulty of
forging it in wrought iron of a proper form, and from other circumstances, is
often cast in gun metal, and consequently must be made to deviate at certain
parts from the desired form which otherwise would be given to it in order
that a metal so easily bent may have the required degree of strength, while at
the same time its weight and cost are in like manner increased.
Now, the object of my said Invention is to give to the propeller and its shaft
and crank the requisite degree of strength to enable them to withstand the
strains to which they are subjected with a very much less weight of metal than
is at present used, or in some cases to give a much greater strength to the said
parts of marine machinery without the necessity of making a corresponding
increase in the weight thereof, and also to diminish the cost of the said parts
of machinery. For this purpose I make suitable moulds of the said propeller
and of its shaft and crank, which moulds I prefer to be made in loam and
baked dry, in a manner well understood in the preparation of moulds for
articles made in cast iron. I prefer, however, that the drying of the moulds
should take place in a stove capable of giving to the mould a low red heat,
whereby any matters capable of assuming the gaseous form that may acci-
dentally have been mixed with the sand or loam will become volatilized previous
to the pouring in of the metal, and into the moulds so prepared I pour or run
steel in a state of fusion; or I use in lieu thereof a mixture of steel and pig
or refined iron, which is somewhat less expensive. The quantity of iron mixed
with the steel will so much depend on the degree of hardness or cohesive force
required as to render it difficult to lay down any fixed rule. The great variety
in the qualities of iron also adds to this difficulty; but I have found for most
purposes from one-half to two-third parts of steel mixed with No. 2 cold
blast Welsh iron give a good result. It will be observed that the propeller,
the shaft, or the crank so produced will be founded in steel, or a mixture of

page_text: steel and iron, the process of casting giving at once the general form and
proportion of each part thereof, in contradistinction to the process of forging
or hammering, by which articles in wrought iron and forged steel are made.
In the manufacture of very massive castings it will be found sufficient to allow
the metal to cool slowly in the mould in order that it may be soft enough to
be filed or turned, but where great toughness is required the casting should be
put into a suitable annealing oven, and-there be kept at a red heat for a period
of time, according to its thickness or the degree of toughness required. In
consequence of the great cohesive force of steel-and its power to resist torsion
as compared with wrought iron, I am enabled to make the propeller and its
shaft and crank of less weight and size than usual without diminishing their
strength; or advantage may be taken of the cohesive force of steel to give
greater stability to the work, keeping the size of the parts the same as are at
present used. It will be also understood that the manufacture of cranks and
shafts for marine steam engines by the process of founding in steel, or a mix-
ture of steel and iron, is also applicable to the manufacture of cranks and shafts
for stationary and locomotive steam engines. The melting of the steel, or a
mixture of steel and pig or refined iron, may be effected in pots, as is at present
practised in the melting of steel, for the purpose of producing bars or rods of
cast steel, in which case a large number of melting pots will be required, and
the workman should as nearly as possible at the same time pour the contents
of the said pots into the mould, or into a channel or channels leading thereto;
but I prefer to melt steel, or a mixture of steel and iron, for the purposes of
this Invention, by an improved mode or modes of melting and casting steel, or
mixtures of steel and iron, as set forth in Provisional Specification of a Patent
for "Improvements in the Manufacture of Cast Steel and Mixtures of Steel
and Cast Iron," bearing even date herewith, and by means of which the steel,
or mixture of steel and iron, may be melted in crucibles of much larger size
than those generally employed in the manufacture of cast steel, and by means
of which Invention great facility is afforded for the running of a large body
of metal at one time into the mould, as described in the Specification of a
Patent granted to me for "Improvements in the Manufacture of Cast Steel
and Mixtures of Steel and Cast Iron," and filed simultaneously with this
present Specification.
Having thus described my Invention, and the manner in which the same is
to be performed, what I claim is,-
Firstly, casting or founding screw propellers in molten steel, or in a mixture
of steel and pig or refined iron.
Secondly. I claim casting or founding the shafts and cranks used for

page_text: driving screw propellers in molten steel, or in a mixture of steel and pig or
refined iron.
Lastly, I claim casting or founding in molten steel, or in a mixture of steel
and pig or refined iron, the shafts and cranks of marine, stationary, and Joco-
motive steam engines.
In witness whereof, I, the said Henry Bessemer, have hereunto set my
hand and seal, this Seventeenth day of December, in the year of
our Lord One thousand eight hundred and fifty-five.
HENRY BESSEMER. (L.s.)
Witness,
T. D. BRANGWIN.