The only remaining difficulty that I had to surmount was the risk of
defects in the surface of the speculum. These sometimes result from the
first splash of the melted metal as it is poured into the ring mould.
The globules sometimes got oxidised before they became incorporated
with the main body of the inflowing molten alloy: and dingy spots in
the otherwise brilliant alloy were thus produced. I soon mastered this,
the only remaining source of defect, by a very simple arrangement.
In place of pouring the melted alloy direct into the ring mould, I
attached to the side of it what I termed a "pouring pocket;"
which communicated with an opening at the lower edge of the ring,
and by a self-acting arrangement by which the mould plate was slightly
tilted up, the influx of the molten alloy advanced in one unbroken
tide. As soon as the entire surface of the mould plate was covered by
the alloy, its weight overcame that of my up-tilting counterpoise,
and allowed the entire apparatus to resume its exact level. The
resulting speculum was, by these simple arrangements, absolutely
perfect in soundness. It was a perfect casting, in all respects worthy
of the care and labour which I invested in its future grinding and
polishing, and enabled it to perform its glorious duties as the grand
essential part of a noble reflecting telescope!
[Image]
A. Chill plate of cast iron turned to the curve of the speculum B.
Turned hoop of wrought iron with opening at O. C. Pouring pocket. D.
Counterpoise, By which the chill plate is tilted up The largest figure
in the engraving is the annealing tub of cast iron filled with sawdust,
where the speculum is placed to cool as slowly as possible.
The rationale of the strength of specula cast in this metal mould
system, as compared with the treacherous brittleness of those cast in
sand moulds, arises simply from the consolidation of the molten metal
pool taking place first at the lower surface, next the metal base of
the mould--the yet fluid alloy above satisfying the contractile
requirements of that immediately beneath it; and so on in succession,
until the last to consolidate is the top or upper stratum.
Thus all risk of contractile tension, which is so dangerously eminent
and inherent in the case of sand-mould castings, made of so exceedingly
brittle an alloy as that of speculum metal, is entirely avoided.
By the employment of these simple and effective improvements in the art
of casting the specula for reflecting telescopes, and also by the
contrivance and employment of mechanical means for grinding and
polishing them, I at length completed my first 8-inch diameter
speculum, and mounted it according to the Newtonian plan. I was most
amply rewarded for all the anxious labour I had gone through in
preparing it, by the glorious views it yielded me of the wonderful
objects in the heavens at night. My enjoyment was in no small degree
enhanced by the pleasure it gave to my father, and to many intimate
friends. Amongst these was Sir David Brewster, who took a most lively
and special interest in all my labours on this subject.
In later years I resumed my telescope making enjoyments, as a
delightful and congenial relaxation from the ordinary run of my
business occupations. I constructed several reflecting telescopes,
of sizes from 10-inch to 20-inch diameter specula. I had also the
pleasure of assisting other astronomical friends, by casting and
grinding specula for them. Among these I may mention my late dear
friend William Lassell, and my excellent friend Warren de la Rue,
both of whom have indelibly recorded their names in the annals of
astronomical science. I know of no subject connected with the pursuit
of science which so abounds with exciting and delightful interest as
that of constructing reflecting telescopes. It brings into play every
principle of constructive art, with the inexpressibly glorious reward
of a more intimate acquaintance with the sublime wonders of the
heavens, I communicated in full detail all my improvements in the art
of casting, grinding, and polishing the specula of reflecting
telescopes, to the Literary and Philosophical Society of Manchester,
illustrating my paper with many drawings. But as my paper was of
considerable length, and as the illustrations would prove costly to
engrave, it was not published in the Society's Transactions. They are
still, however, kept in the library for reference by those who take a
special interest in the subject.
1829. A Mode of transmitting Rotary Motion by means of a Flexible
Shaft, formed of a Coiled Spiral Wire or Rod of Steel.
While assisting Mr. Maudslay in the execution of a special piece of
machinery, in which it became necessary to have some holes drilled in
rather inaccessible portions of the work in hand, and where the
employment of the ordinary drill was impossible, it occurred to me that
a flexible shaft, formed of a closely coiled spiral of steel wire,
might enable us to transmit the requisite rotary motion to a drill
attached to the end of this spiral shaft. Mr. Maudslay was much pleased
with the notion, and I speedily put it in action by a close coiled
spiral wire of about two feet in length.
This was found to transmit the requisite rotary motion to the drill at
the end of the spiral with perfect and faithful efficiency.
The difficulty was got over, to Mr. Maudslay's great satisfaction.
So far as I am aware, such a mode of transmitting rotary motion was new
and original. The device was useful, and proved of essential service in
other important applications. By a suitably close coiled spiral steel
wire I have conveyed rotary motion quite round an obstacle, such as is
indicated in the annexed figure.
[Image]
It has acted with perfect faithfulness from the winch handle at A to
the drill at B. Any ingenious mechanic will be able to appreciate the
value of such a flexible shaft in many applications. Four years ago I
saw the same arrangement in action at a dentist's operating-room, when
a drill was worked in the mouth of a patient to enable a decayed tooth
to be stopped. It was said to be the last thing out in "Yankee notions."
It was merely a replica of my flexible drill of 1829.
1829. A Mode of cutting Square or Hexgonal Collares Nuts or Bolt-Heads
by means of a Revolving File or Cutter.
This method is refrered to, and drawings given, in the text,
pp. 141, 142.
1829. A Investigation into the Origin and Mode of writing the Cuneiform
Character
This will be found described in the next and final chapter
1836. A Machine for cutting the Key-Grooves in Metal Wheels and Belt
Pulleys, of ANY Diameter.
The fastening of wheels and belt pulleys to shafts, so as to enable
them to transmit rotary motion, is one of the most frequently-recurring
processes in the construction of machinery. This is best effected by
driving a slightly tapered iron or steel wedge, or "key" as it is
technically termed, into a corresponding recess, or flat part of the
shaft, so that the wheel and shaft thus become in effect one solid
structure.
The old mode of cutting such key-grooves in the eyes of wheels was
accomplished by the laborious and costly process of chipping and
filing. Maudslay's mortising machine, which he contrived for the Block
machinery, although intended originally to operate upon wood, contained
all the essential principles and details required for acting on metals.
Mr. Richard Roberts, by some excellent modifications, enabled it to
mortise or cut out the key-grooves in metal wheels, and this method
soon came into general use. This machine consisted of a vertical slide
bar, to the lower end of which was attached the steel mortising tool,
which received its requisite up and down motion from an adjustable
crank, through a suitable arrangement of the gearing. The wheel to be
operated upon was fixed to a slide-table, and gradually advanced,
so as to cause the mortising tool to take successive cuts through the
depth of the eye of the wheel, until the mortise or key-groove had
attained its required depth.
The only drawback to this admirable machine was that its service was
limited in respect to admitting wheels whose half diameter did not
exceed the distance from the back of the jaw of the machine to the face
of the mortise tool; so that to give to this machine the requisite
rigidity and strength to resist the strain on the jaw, due to the
mortising of the key-grooves, in wheels of say 6 feet diameter,
a more massive and cumbrous frame work was required, which was most
costly in space as well as in money.
In order to obviate this inconvenience, I designed an arrangement of a
key-groove mortising machine. It was capable of operating upon wheels
of any diameter, having no limit to it capacity in that respect.
It was, at the same time, possessed in respect of the principle on
which it was arranged, of the power of taking a much deeper cut,
there being an entire absence of any source of springing or elasticity
in its structure. This not only enabled the machine to perform its work
with more rapidity, but also with more precision. Besides, it occupied
much less space in the workshop, and did not cost above one-third of
the machines formerly in use. It gave the highest satisfaction to those
who availed themselves of its effective Services.
[Image]
A comparison of Fig. 1--which represents the general arrangement of
the machine in use previous to the introduction of mine--with that of
Fig. 2, may serve to convey some idea of their relative sizes. Fig. 1
shows a limit to the admission of wheels exceeding 6 feet diameter,
Fig. 2 shows an unlimited capability in that respect.
1836. An Instrument for finding and marking the Centres of Cylindrical
Rods or Bolts about to be turned on the Lathe.
One of the most numerous details in the structure of all classes of
machines is the bolts which serve to hold the various parts together.
As it is most important that each bolt fits perfectly the hole it
belongs to, it is requisite that each bolt should, by the process of
turning, be made perfectly cylindrical. In preparing such bolts,
as they come from the forge, in order to undergo the process of
turning, they have to be "centred;" that is, each end has to receive a
hollow conical indent, which must agree with the axis of the bolt.
To find this in the usual mode, by trial and frequent error, is a most
tedious process, and consumes much valuable time of the workman as well
as his lathe.
[Image]
In order to obviate the necessity for this costly process, I devised
the simple instrument, a drawing of which is annexed. The use of this
enabled any boy to find and mark with absolute exactness and rapidity
the centres of each end of bolts, or suchlike objects. All that was
required was to place the body of the bolt in the V-shaped supports,
and to gently cause it to revolve, pressing it longitudinally against
the steel-pointed marker, which scratched a neat small circle in the
true centre or axis of the bolt. This small circle had its centre
easily marked by the indent of a punch, and the work was thus ready for
the lathe. This humble but really important process was accomplished
with ease, rapidity, and great economy.
1836. Improvement in Steam-Engine Pistons, and in Water and Air-Pump
Buckets, so as to lessen Friction and dispense with Packing.
The desire to make the pistons of steam-engines and air-pump buckets of
condensing engines perfectly steam and water tight has led to the
contrivance of many complex and costly constructions for the purpose of
packing them. When we take a commonsense view of the subject, we find
that in most cases the loss of power resulting from the extra friction
neutralises the expected saving. This is especially the case with the
air-pump bucket of a condensing steam-engine, as it is in reality much
more a water than an air pump. But when it is constructed with a deep
well-fitted bucket, entirely without packing, the loss sustained by
such an insignificant amount of leakage as may occur from the want of
packing is more than compensated by the saving of power resulting from
the total absence of friction.
The first condensing steam-engine to which I applied an air-pump
bucket, entirely without packing, was the forty horsepower engine,
which I constructed for the Bridgewater Foundry. It answered its
purpose so well that, after twenty years' constant working,
the air-pump cover was taken off, out of curiosity, to examine the
bucket, when it was found in perfect order. This system, in which I
dispensed with the packing for air-pump buckets of condensing
steam-engines, I have also applied to the pistons of the steam
cylinders, especially those of high-pressure engines of the smaller
vertical construction, the stroke of which is generally short and
rapid. Provided the cylinder is bored true, and the piston is carefully
fitted, and of a considerable depth in proportion to its diameter,
such pistons will be found to perform perfectly all their functions,
and with a total absence of friction as a direct result of the absence
of packing. By the aid of our improved machine tools, cylinders can now
be bored with such perfect accuracy, and the pistons be fitted to them
with such absolute exactness, that the small quantity of water which
the steam always deposits on the upper side of the piston, not only
serves as a frictionless packing, but also serves as a lubricant of the
most appropriate kind. I have applied the same kind of piston to
ordinary water-pumps, with similar excellent results. In most cases of
right packed pistons we spend a shilling--to save sixpence--
a not unfrequent result of "so-called" refined improvements.
1836. An instantaneous Mode of producing graceful Curves, suitable for
designing Vases and other graceful objects in Pottery and Glass.
The mode referred to consists in giving a rapid "switch" motion to a
pencil upon a piece of paper, or a cardboard, or a smooth metal plate;
and then cutting out the curve so produced, and employing it as a
pattern or "template," to enable copies to be traced from it.
When placed at equal distances, and at equal angles on each side of a
central line, so as to secure perfect symmetry of form according to the
nature of the required design, the beauty of these "instantaneous"
curves, as I term them, arises from the entire absence of any sudden
variation in their course. This is due to the momentum of the hand when
"switching" the pencil at a high velocity over the paper.
By such simple means was the beautiful curve produced, which is given
on the following page. It was produced "in a twinkling," if I may use
the term to express the rapidity with which it was "switched."
The chief source of the gracefulness of these curves consists in the
almost imperceptible manner in which they pass in their course from one
degree of curvature into another. I have had the pleasure of showing
this simple mode of producing graceful curves to several potters,
who have turned the idea to good account. The illustrative figures on
the next page have all been drawn from "templates" whose curves were
"switched" in the manner of Fig. A.
[Image]
1836. A Machine for planing the smaller or detail parts of Machinery,
whether Flat or Cylindrical.
Although the introduction of the planing machine into the workshops of
mechanical engineers yielded results of the highest importance in
perfecting and economising the production of machinery generally, yet,
as the employment of these valuable machine tools was chiefly intended
to assist in the execution of the larger parts of machine manufacture,
a very considerable proportion of the detail parts still continued to
be executed by hand labour, in which the chisel and the file were the
chief instruments employed. The results were consequently very
unsatisfactory, both as regards inaccuracy and costliness.
[image]
With the desire of rendering the valuable services of the Planing
Machine applicable to the smallest detail parts of machine manufacture,
I designed a simple and compact modification of it, such as should
enable any attentive lad to execute all the detail parts of the
machines in so unerring and perfect a manner as not only to rival the
hand work of the most skilful mechanic, but also at such a reduced cost
as to place the most active hand workman far into the background.
The contrivance I refer to is usually known as "Nasmyth's Steam Arm."
None but those who have had ample opportunities of watching the process
of executing the detail parts of machines, can form a correct idea of
the great amount of time that is practically wasted and unproductive,
even when highly-skilled and careful workmen are employed. They have so
frequently to stop working, in order to examine the work in hand,
to use the straight edge, the square, or the calipers, to ascertain
whether they are "working correctly." During that interval, the work is
making no progress: and the loss of time on this account is not less
than one-sixth of the working hours, and sometimes much more;
though all this lost time is fully paid for in wages.
[Image] Apparatus for enabling the machine to execute segmented work
But by the employment of such a machine as I describe, even when placed
under the superintendence of well-selected intelligent lads, in whom
the faculty of good sight and nicety of handling is naturally in a high
state of perfection, any deficiency in their physical strength is amply
compensated by these self-acting machines. The factory engine supplies
the labour or the element of Force, while the machines perform their
work with practical perfection. The details of machinery are thus
turned out with geometrical accuracy, and are in the highest sense
fitted to perform their intended purposes.
1837. Solar Ray Origin of the form of the Egyptian Pyramids, Obelisks,
etc.
This will be found described summarily in the next and final chapter.
1837. Method of reversing the action of Slide Lathes.
In the employment of Slide Turning Lathes, it is of great advantage to
be able to reverse the motion of the Slide so as to enable the turning
tool to cut towards the Head of the Lathe or away from it, and also to
be able to arrest the motion of the Slide altogether, while all the
other functions of the lathe are continued in action. All these objects
are attained by the simple contrivance represented in the annexed
illustration.
[Image]
It consists of a lever E, moving on a stud-pin S, attached to the back
of the head stock of the lathe T. This lever carries two wheels of
equal diameter marked B and G. These wheels can pitch into a
corresponding wheel A, fixed on the back end of the lay spindle.
When the handle of the lever E is depressed (as seen in the drawing)
the wheel B is in gear with wheel A. while C is in gear with the
slidescrew wheel D, and so moves the slide (say from the Head Stock of
the lathe). On the other hand, when the lever E is elevated in position
E", wheel B is taken out of gear with A, while G is put in gear with A,
and B is put in gear with D; and thus the Slide is caused to move
towards the Head Stock of the lathe. Again, where it is desired to
arrest the motion of the Slide altogether, or for a time, as occasion
may require, the lever handle is put into the intermediate position E',
which entirely severs the communication between A and D, and so arrests
the motion of the slide. This simple contrivance effectually served all
its purposes, and was adopted by many machine tool-makers and
engineers.
1838. Self-adjusting Bearings for the Shafts of Machinery
A frequent cause of undue friction and heating of rapidly rotating
machinery arises from some inaccuracy or want of due parallelism
between the rotating shaft or spindle and its bearing. This is
occasioned in most cases by some accidental change in the level of the
supports of the bearings. Many of the bearings are situated in dark
places, and cannot be seen. There are others that are difficult of
access--as in the case of bearings of screw-propeller shafts.
Serious mischief may result before the heating of the bearing proclaims
its dangerous condition. In some cases the timber work is set on fire,
which may result in serious consequences.
In order to remove the cause of such serious mischief, I designed an
arrangement of bearing, which enabled it, and the shaft working in it,
to mutually accommodate themselves to each other under all
circumstances, and thus to avoid the danger of a want of due and mutual
parallelism in their respective axes. This arrangement consisted in
giving to the exterior of the bearing a spherical form, so as, within
moderate limits, to allow it to accommodate itself to any such changes
in regard to mutual parallelism, as above referred to. In other cases,
I employed what I may call Rocking centres, on which the Pedestal or
"Plumber Block" rested; and thus supplied a self-adjusting means for
obviating the evils resulting from any accidental change in the proper
relative position of the shaft and its bearing. In all cases in which I
introduced this arrangement, the results were most satisfactory.
In the case of the bearings of Blowing Fans, in which the rate of
rotation is naturally excessive, a spherical resting-place for the
bearings enabled them to keep perfectly cool at the highest speed.
This was also the case in the driving apparatus for machine tools,
which is generally fixed at a considerable height above the machine.
These spherical or self-adjusting bearings were found of great service.
The apparatus, being generally out of convenient reach, is apt to get
out of order unless duly attended to. But, whether or not, the saving
of friction is in itself a reason for the adoption of such bearings.
This may appear a trifling technical matter of detail; but its great
practical value must be my excuse for mentioning it.
1838. Invention of Safety Foundry Ladle.
The safety ladle is described in the text, p. 202.
1838. Invention of the Steam Ram
My invention was made at this early date, long before the attack by the
steam-ram Merrimac upon the Cumberland, and other ships, in Hampton Roads,
United States. I brought my plans and drawings under the notice of the
Admiralty in 1845; but nothing was done for many years. Much had been
accomplished in rendering our ships shot-proof by the application of
iron plates; but it appeared to me that not one of them could exist
above water after receiving on its side a single blow from an
iron-plated steam-ram of 2000 tons. I said, in a letter to the Times,
"As the grand object of naval warfare is the destruction by the most
speedy mode of the ships of the enemy, why should we continue to
attempt to attain this object by making small holes in the hull of the
enemy when, by one single masterly crashing blow from a steam ram,
we can crush in the side of any armour-plated ship, and let the water
rush in through a hole, 'not perhaps as wide as a church door or as
deep as a well, but 'twill serve'; and be certain to send her below
water in a few minutes.*
[footnote...
In these days of armour-clad warships, when plates of enormous
thickness are relied on as invulnerable, our Naval Constructors appear
to forget that the actual structural strength of such ships depends on
the backing of the plates, which, be it ever so thick, would yield to
the cramming blow of a moderate-sized Ram.
...]
I published my description of the steam ram and its apparatus in the
Times of January 1853, and again addressed the Editor on the subject
in April 1862. General Sir John Burgoyne took up the subject,
and addressed me in the note at the foot of this page.*
[footnote...
The following is the letter of General Sir John Burgoyne:
WAR OFFICE, PALL MALL, LONDON, 8th April 1862.
"General Sir John Burgoyne presents his compliments to Mr. Nasmyth,
and was much pleased to find, by Mr. Nasmyth's letter in the Times of
this day, certain impressions that he has held for some time confirmed
by so good an authority. "A difficulty seems to be anticipated by many
that a steamer used as a ram with high velocity, if impelled upon a
heavy ship, would, by the revulsion of the sudden shock, be liable to
have much of her gear thrown entirely out of order, parts displaced,
and perhaps the boilers burst. Some judgment, however, may be formed on
this point by a knowledge of whether such circumstances have occurred
on ships suddenly grounding; and even so, it may be a question whether
so great a velocity is necessary. "An accident occurred some twenty
years ago, within Sir John Burgoyne's immediate cognisance, that has
led him particularly to consider the great power of a ship acting as a
ram. A somewhat heavy steamer went, by accident or mismanagement, end
on to a very substantial wharf wall in Kingstown Harbour, Dublin Bay.
Though the force of the blow was greatly checked through the measures
taken for that purpose, and indeed so much so that the vessel itself
suffered no very material injury, yet several of the massive granite
stones of the facing were driven some inches in, showing the enormous
force used upon them. "Superior speed will be very essential to the
successful action of the ram; but by the above circumstance we may
assume that even a moderate speed would enable great effects to be
produced, at least on any comparatively weak point of even ironclad
ships, such as the rudder."
...]
In June 1870, I received a letter from Sir E. J. Reed, containing the
following extracts: --"I was aware previously that plans had been
proposed for constructing unarmoured steam rams, but I was not
acquainted with the fact that you had put forward so well-maturerd a
scheme at so early a date; and it has given me much pleasure to find
that such is the case. It has been a cause both of pleasure and
surprise to me to find that so long ago you incorporated into a design
almost all the features which we now regard as essential to ramming
efficiency--twin screws and moderate dimensions for handiness,
numerous water-tight divisions for safety, and special strengthenings
at the bow. Facts such as these deserve to be put on record....
Meanwhile accept my congratulations on the great skill and foresight
which your ram-design displays."
Collisions at sea unhappily afford ample evidence of the fatal
efficiency of the ramming principle. Even ironclad ships have not been
able to withstand the destructive effect. The Vanguard and the Kurfurst
now lie at the bottom of the sea in consequence of an accidental
"end-on" ram from a heavy ship going at a moderate velocity. High speed
in a Steam Ram is only desirable when the attempt is made to overtake
an enemy's ship; but not necessary for doing its destructive work.
A crash on the thick plates of the strongest Ironclad, from a Ram of
2000 tons at the speed of four miles an hour, would drive them inwards
with the most fatal results.
1839. Invention of the Steam Hammer, in its general principles and
details.
Described in text, p. 231.
1839. Invention of the Floating Mortar or Torpedo Ram.
For particulars and details, see Report of Torpedo Committee.
1839. A Double-faced Wedge-shaped Sluice-Valve for Main Street
Water-pipes.
The late Mr. Wicksteed, engineer of the East London Water Company,
having stated to me the inconvenience which had been experienced from
the defects in respect of water-tightness, as well as the difficulty of
opening and closing the valves of the main water-pipes in the streets,
I turned my attention to the subject. The result was my contrivance of
a double-faced wedge-shaped sluice-valve, which combined the desirable
property of perfect water-tightness with ease of opening and closing
the valve.
This was effected by a screw which raised the valve from its bearings
at the first partial turn of the screw, after which there was no
further resistance or friction, except the trifling friction of the
screw in its nut on the upper part of the sluice-valve. When screwed
down again, it closed simultaneously the end of the entrance pipe and
that of the exit pipe attached to the valve case in the most effective
manner.
[image]
Mr. Wicksteed was so much pleased with the simplicity and efficiency of
this valve that he had it applied to all the main pipes of his Company.
When its advantages became known, I received many orders from other
water companies, and the valves have since come into general use.
The prefixed figure will convey a clear idea of the construction.
The wedge form of the double-faced valve is conspicuous as the
characteristic feature of the arrangement.*
[footnote...
At a meeting of the Institution of Civil Engineers, May 23, 1883,
when various papers were read on Waterworks, Mr. H. I. Marten observed
in the course of the discussion: --"It has been stated in Mr. Gamble's
paper (on the waterworks of Port Elizabeth) that the sluice valves are
of the usual pattern. The usual patterns of the present day are in
wonderful advance of those of thirty or forty years since. The great
improvement originated with the introduction of 'the double-faced
sluice-cock.' This sluice-cock, which had now superseded every other
description, was the creation of Mr. James Nasmyth's inventive genius.
Mr. Marten said he well remembered the first reception of this useful
invention, as he happened at that time to be a pupil of Mr. Thomas
Wicksteed. He was present when Mr. Wicksteed explained to Mr. Nasmyth
the want he had experienced of a sluice-cock for Waterworks purposes,
which should shut and remain perfectly tight against a pressure coming
from either side. Mr. Marten had a lively recollection of the
instantaneous rapidity with which Mr. Nasmyth not only grasped but
provided for the requirement; so that almost by the time Mr. Wicksteed
had completed the statement of his want, Mr. Nasmyth had drawn upon the
back of an old letter a rough sketch of the first double-faced
sluice-cock; and in less than an hour had converted this rough sketch
into a full-sized working drawing; in the preparation of which it fell
to Mr. Marten's lot to have the honour to assist. In his
'Autobiography' Mr. Nasmyth referred to the conversation with
Mr. Wicksteed, and introduced a print of the drawing made upon the
occasion. The invention has been of the greatest use to the Waterworks
Engineer, especially in connection with the constant supply system, in
which it frequently happened that the pressure was sometimes against
one face of the sluice-cock, and sometimes against the other."--
See Proceedings and Discussions of the Institution of Civil Engineers,
1883, pp. 88, 89.
...]
1839. A Hydraulic Mattress Press, capable of exerting a pressure of
Twenty thousand tons.
Being under the impression that there are many processes in the
manufacturing arts, in which a perfectly controllable compressing power
of vast potency might be serviceable, I many years ago prepared a
design of an apparatus of a very simple and easily executed kind,
which would supply such a desideratum. It was possessed of a range of
compressing or squeezing power, which far surpassed anything of the
kind that had been invented. As above said, it was perfectly
controllable; so as either to yield the most gentle pressure, or to
possess the power of compressing to upwards of twenty thousand tons;
the only limit to its power being in the materials employed in its
construction.
The principle of this enormously powerful compressing machine is
similar to that of the Hydraulic Press; the difference consisting
principally in the substitution of what I term a Hydraulic Mattress in
place of the cylinder and ram of the ordinary hydraulic press.
The Hydraulic Mattress consists of a square or circular water-tight
vessel or flat bag formed of 1/2-inch thick iron or steel plates
securely riveted together; its dimensions being, say 15 feet square by
3 feet deep, and having semicircular sides, which form enables the
upper flat part of the Mattress to rise say to the extent of 6 inches,
without any injury to the riveted joints, as such a rise or alteration
of the normal form of the semicircular sides would be perfectly
harmless, and not exceed their capability of returning to their normal
curve when the 6-inch rise was no longer necessary, and the elevating
pressure removed.
[image]
The action of this gigantic press is as follows. The Mattress A A
having been filled with water, an additional quantity is supplied by a
force pump, capable of forcing in water with a pressure of one ton to
the square inch; thus acting on an available surface of at least 144
square feet surface--namely, that of the upper flat surface of the
Mattress. It will be forced up by no less a pressure than twenty
thousand tons, and transfer that enormous pressure to any article that
is placed between the rising table of the press and the upper table.
When any object less thick than the normal space is required to receive
the pressure, the spare space must be filled with a suitable set of
iron flat blocks, so as to subject the article to be pressed to the
requisite power.
As before stated, there may be many processes in the manufacturing arts
in which such an enormous pressure may be useful; and this can be
accomplished with perfect ease and certainty. I trust that this account
of the principles and construction of such a machine may suggest some
employment worthy of its powers. In the general use of the Mattress
press, it would be best to supply the pressure water from an
accumulator, which should be kept constantly full by the action of
suitable pumps worked by a small steam-engine. The great press would
require the high-pressure water only now and then; so that it would not
be necessary to wait for the small pump to supply the pressure water
when the Mattress was required to be in action.
1840. A Tapping Square, or instrument by which Perfect Verticality of
the Tapping of Screwed Holes is insured.
[image]
The letter X shows how Screws are frequently made when tapped in the
old mode; the letter T as they are always made when the Tapping Square
is employed.
1840. A Mode of turning Segmental Work in the Ordinary Lathe
In executing an order for twenty locomotive engines for the Great
Western Railway Company, there was necessarily a repetition of detail
parts. Many of them required the labour of the most skilful workmen,
as the parts referred to did not admit of their being executed by the
lathe or planing-machine in their ordinary mode of application.
But the cost of their execution by hand labour was so great, and the
risk of inaccuracy was so common (where extreme accuracy was essential),
that I had recourse to the aid of special mechanical contrivances and
machine tools for the purpose of getting over the difficulty.
The annexed illustration has reference to only one class of objects in
which I effected great saving in the production, as well as great
accuracy in the work. It refers to a contrivance for producing by the
turning-lathe the eighty bands of the eccentrics for these twenty
engines. Being of a segmental form, but with a projection at each
extremity, which rendered their production and finish impossible by the
ordinary lathe, I bethought me of applying what is termed the mangle
motion to the rim of a face plate of the lay, with so many pins in it
as to give the required course of segmental motion for the turning tool
to operate upon, between the projections C C in the illustration.
[image]
I availed myself of the limited to-and-fro horizontal motion of the
shaft of the mangle motion wheel, as it, at each end of the row of pegs
--in the face plate (when it passes from the exterior to the interior
range of them) in giving the feed motion to the tool in; the slide
rest, "turned" the segmental exterior of the eccentric hoops.
This it did perfectly, as the change of position of the small shaft
occurred at the exact time when the cut was at its termination,--that
being the correct moment to give the tool "the feed, or advance for the
taking of the next cut. The saving, in respect to time, was 10 to 1 in
comparison with the same amount of work done by hand labour; while the
"truth" or correctness of the work done by this handy little
application of the turning-lathe was absolutely perfect I have been the
more particular in my allusion to this contrivance, as it is applicable
to any lathe, and can perform work which no lathe without it can
accomplish. The unceasing industry of such machines is no small
addition to their attractions, in respect to the production of
unquestionably accurate work.
1843. Invention of the Steam Hammer Pile-driver.
Described in text, p. 261.
1843. A Universal Flexible Joint for Steam and Water-pipes.
[Image]
The chief novelty in this swivel joint is the manner in which the
packing of the joints is completely enclosed, thereby rendering them
perfectly and permanently watertight.
1844. An Improvement in Blowing Fans and their Bearings.
The principle on which Blowing Fans act, and to which they owe their
efficiency, consists in their communicating Centrifugal action to the
air within them.
In order to obtain the maximum force of blast, with the minimum
expenditure of power, it is requisite so to form the outside rim of the
Fan-case as that each compartment formed by the space between the ends
of the blades of the Fan shall in its course of rotation possess an
equal facility of exit for the passage of the air it is discharging.
Thus, in a Fan with six blades, the space between the top of the blades
and the case of the Fan should increase in area in the progressive
ratios of 1-2-3-4-5-6.
[Image]
If a Fan be constructed on this common-sense principle, we shall secure
the maximum of blast from the minimum of driving power. And not only so;
but the humming sound--so disagreeable an accompaniment to the action
of the Fans (being caused by the successive sudden escape of the air
from each compartment as it comes opposite the space where it can
discharge its confined block of air)--will be avoided. When the outer
case of a Fan is formed on the expanding or spiral principle,
as above described, all these important advantages will attend its use.
As the inward current of air rushes in at the circular openings on each
side of the Fan-case, and would thus oppose each other if there was a
free communication between them, this is effectually obviated by
forming the rotating portion of the fan by a disc of iron plate,
which prevents the opposite in-rushing currents from interfering with
each other, and at the same time supplies a most substantial means of
fastening the blades, as they are conveniently riveted to this central
disc. On the whole, this arrangement of machinery supplies a most
effective "Noiseless Blowing Fan."
1845. A direct Action "Suction" Fan for the Ventilation of Coal-Mines.
The frequency of disastrous colliery explosions induced me to give my
attention to an improved method for ventilating coal mines.
The practice then was to employ a furnace, placed at the bottom of the
upcast shaft of the coal-pit, to produce the necessary ventilation.
This practice was highly riskful. It was dangerous as well as
ineffective. It was also liable to total destruction when an explosion
occurred, and the means of ventilation were thus lost when it was most
urgently required. The ventilation of mines by a current of air forced
by a Fan into the workings, had been proposed by a German named George
Agricola, as far back as 1621. The arrangement is found figured in his
work entitled De Re Metalicat, p. 162. But in all cases in which this
system of forcing air through the workings and passages of a mine has
been tried, it has invariably been found unsuccessful as a means of
ventilation.
As all rotative Blowing Fans draw in the air at their centres,
and expel it at their circumference, it occurred to me that if we were
to make a communication between the upcast shaft of the mine and the
centre or suctional part of the Fan closing the top of the upcast
shaft, a Fan so arranged would draw out the foul air from the mine,
and allow the fresh air to descend by the downcast shaft,
and so traverse the workings. And as a Suction Fan so placed would be
on the surface of the ground, and quite out of the way of any risk of
injury--being open to view and inspection at all times--we should
thus have an effective and trustworthy means for thorough ventilation.
[Image]
Having communicated the design for my Direct Action Suction Fan for
coal-pit ventilation to the Earl Fitzwilliam, through his agent
Mr. Hartop, in 1850, his lordship was so much pleased with it that I
received an order for one of 14 feet diameter, for the purpose of
ventilating; one of his largest coalpits. I arranged the steam-engine
which gave motion to the large Fan, so as to be a part of it;
and by placing the crank of the engine on the end of the Fan-shaft,
the engine transferred its power to it in the most simple and direct
manner. The high satisfaction which this Ventilating Fan gave to the
Earl and to all connected with his coal-mines, led to my receiving
orders for several of them.
I took out no patent for the invention, but sent drawings and
descriptions to all whom I knew to be interested in coalmine ventilation.
I read a paper on the subject, and exhibited the necessary drawings, at
the meeting of the British Association at Ipswich in 1851. These were
afterwards published in the Mining Journal. The consequence is that
many of my Suction Ventilating Fans are now in successful action at
home and abroad.
1845. An improvement in the Links of Chain Cables.
1845. An Improved Method of Welding Iron.
One of the most important processes in connection with the production
of the details of machinery, and other purposes in which malleable iron
is employed, is that termed welding, namely, when more or less complex
forms are, so to speak, "built up" by the union of suitable portions of
malleable iron united and incorporated with each other in the process
of welding. This consists in heating the parts which we desire to unite
to a white heat in a smith's forge fire, or in an air furnace, by means
of which that peculiar adhesive "wax-like" capability; of sticking
together is induced,--so that when the several parts are forcibly
pressed into close contact by blows of a hammer, their union is
rendered perfect.
But as the intense degree of heat which is requisite to induce this
adhesive quality is accompanied by the production of a molten oxide of
iron that clings tenaciously to the white-hot surfaces of the iron,
the union will not be complete unless every particle of the adhesing
molten scoriae is thoroughly discharged and driven out from between the
surfaces we desire to unite by welding. If by any want of due care on
the part of the smith, the surfaces be concave or have hollows in them,
the scoriae will be sure to lurk in the recesses, and result in a
defective welding of a most treacherous nature. Though the exterior may
display no evidence of the existence of this fertile cause of failure,
yet some undue or unexpected strain will rend and disclose the shut-up
scoriae, and probably end in some fatal break-down. The annexed figures
will perhaps serve to render my remarks on this truly important subject
more clear to the reader.
[Image]
Fig.1 represents an imperfectly prepared surface of two pieces of
malleable iron about to be welded. The result of their concavity of
form is that the scoriae are almost certain to be shut up in the hollow
part,--as the pieces will unite first at the edges and thus include
the scoriae, which no amount of subsequent hammering will ever
dislodge. They will remain lurking between, as seen in Fig.2. Happily,
the means of obviating all such treacherous risks are as simple as they
are thoroughly effective. All that has to be done to render their
occurrence next to impossible is to give to the surfaces we desire to
unite by welding a convex form as represented in Fig. 3; the result of
which is that we thus provide an open door for the scoriae to escape
from between the surfaces,--as these unite first in the centre, as
due to the convex form, and then the union proceeds outwards, until
every particle of scoriae is expelled, and the union is perfectly
completed under the blows of the hammer or other compressing agency.
Fig. 4 represents the final and perfect completion of the welding,
which is effected by this common-sense and simple means,--that is,
by giving the surfaces a convex form instead of a concave one.
When I was called by the Lords of the Admiralty in 1846 to serve on a
Committee, the object of which was to investigate the causes of failure
in the wrought-iron smith work of the navy, many sad instances came
before us of accidents which had been caused by defective welding,
especially in the vitally important articles of Anchors and Chain Cables.
In the case of the occasional failure of chain cables, the cause was
generally assigned to defective material; but circumstances led me to
the conclusion that it was a question of workmanship or maltreatment of
what I knew to be of excellent material. I therefore instituted a
series of experiments which yielded conclusive evidence upon the
subject; and which proved that defective welding was the main and chief
cause of failure. In order to prove this, several apparently excellent
cables were, by the aid of "the proving machine," pulled to pieces,
link by link, and a careful record was kept of the nature of the
fracture. The result was, that out of every 100 links pulled asunder
80 cases clearly exhibited defective welding; while only 20 were broken
through the clear sound metal. This yielded a very important lesson to
those specially concerned.
1845. Introduction of the V Anvil.
In connection with my Steam Hammer, when employed in forging great
cylindrical shafts, I introduced what I termed my V anvil.
Its employment has most importantly contributed to secure perfect
soundness in such class of forgings.
In the old system of forging cylindrical shafts, the bar was placed
upon a flat-faced anvil. The effect of each blow of the hammer upon the
work was to knock the shaft into an oval form (see Fig. 1); and the
inevitable result of a succession of such blows was destruction of the
soundness of the centre or axis of the shaft.
[image]
In order to remedy this grave defect, arising from the employment of a
flat-faced anvil, I introduced my V anvil face (see Fig. 2), the effect
of which was, that the dispersive action of the blow of the hammer was
changed into a converging action, which ensured the perfect soundness
of the work; while the V or fork-like form of the angle face kept the
work steadily under the centre of the hammer, allowing the scale or
scoriae to fall into the apex or bottom of the V, which thus passed
away, leaving the faces of the angle quite clear.
This simple and common-sense improvement was eagerly and generally
adopted, and has been productive of most satisfactory and important
results.
1847. A Spherical-seated Direct-weighted Safety Valve.
Having been on several occasions called to investigate the causes of
steam boiler explosions, my attention was naturally directed to the
condition of the Safety Valve. I found the construction of them in many
cases to be defective in principle as well as in mechanical details;
resulting chiefly from the employment of a conical form in the valve,
which necessitated the use of a guide spindle to enable it to keep in
correct relative position to its corresponding conical seat, as seen at
A in Fig. 1. As this guide spindle is always liable to be clogged with
the muddy deposit from the boiling water, which yields a very adhesive
encrustation, the result is a very riskful tendency to impede the free
action of the Safety Valve, and thereby prevent its serving its
purpose.
[image]
With a view to remove all such causes of uncertainty in the action of
this vitally important part of a steam boiler I designed a Safety Valve,
having a spherical valve and corresponding seat, as seen in B C,
Fig. 2. This form of Safety Valve had the important property of fitting
to its bearing-seat in all positions, requiring no other guide than its
own spherical seat to effect that essential purpose. And as the weight
required to keep the valve closed until the exact desired maximum
pressure of steam has been attained, is directly attached to the under
side of the valve by the rod, the weight, by being inside the boiler,
is placed out of reach from any attempt to tamper with it.
The entire arrangement of this Safety Valve is quite simple. It is free
from all Lever Joints and other parts which might become clogged;
and as there is always a slight pendulous motion in the weight by the
action of the water in the boiler, the spherical surfaces of the valve
and its seat are thus ever kept in perfect order. As soon as the
desired pressure of steam has been reached, and the gravity of the
weight overcome, the valve rises from its seat, and gives perfectly
free egress to any farther accumulation of steam. It is really quite a
treat, in its way, to observe this truly simple and effective Safety
Valve in action. After I had contrived and introduced this Safety
Valve, its valuable properties were speedily acknowledged, and. its
employment has now become very general.
1847. A Machine for cutting out Cottar Slots and Key-Groove Recesses in
Parts of Machinery by a Traversing Drill.
One of the most tedious and costly processes in the execution of the
detail parts of machinery is the cutting out of Cottar Slots in piston
rods, connecting rods, and key recesses in shafts. This operation used
to be performed by drilling a row of holes through the solid body of
the object, and then chipping away the intermediate metal between the
holes, and filing the rude slot, so produced, into its required form.
The whole operation, as thus conducted, was one of the most tedious and
irksome jobs that an engineer workman could be set to, and could only
be performed by those possessed of the highest skill.
