James Nasmyth.

James Nasmyth, engineer; an autobiography online

. (page 33 of 37)
Online LibraryJames NasmythJames Nasmyth, engineer; an autobiography → online text (page 33 of 37)
Font size
QR-code for this ebook


classes of machines is the bolts which serve to hold the various
parts together. As it is most important that each bolt fits per-




fectly 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.

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 such-
like objects. All that was required was to place the body of
the bolt in the V-shaped supports, and to gently cause it to re-



400 INVENTIONS AND CONTRIVANCES. CHRON. LIST.

volve, 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 ivith 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 construc-
tions for the purpose of packing them. When we take a common-
sense 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 horse-
power engine, which I constructed for the Bridgewater Foundry.
It answered its purpose so well that, after twenty years' con*
stant 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



CHRON. LIST. INVENTIONS AND CONTRIVANCES. 401

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 pro-
duced, 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 twink-
ling," 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.

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

2D



402 INVENTIONS AND CONTRIVANCES. CHKOX. LIST.




j



CHROX. LIST. INVENTIONS AND CONTRIVANCES.



403



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 un-
satisfactory, both as regards inaccuracy and costliness.




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 watch-



401



INVENTIONS AND CONTRIVANCES. CHBON. LIST.



ing the process of executing the detail parts of machines, can
form a correct idea of the great amount of time that is practi-
cally 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 inter-
val, 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.

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
tlr6 thus turned out with geometrical accuracy,




APPARATUS FOR



CUTE SEGMENTED an( i are j n the highest sense fitted to perform
their intended purposes.

1837. Solar Ray Origin of the form of the Egyptian Pyramid^
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 t/te 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 ;nv
continued in action. All these objects are attained by the
simple contrivance represented in the annexed illustration. It
consists of a lever JO, moving on a stud-pin S, attached to the



CHRON. LIST. INVENTIONS AND CONTRIVANCES.



405



back of the head stock of the lathe T. This lever carries two
wheels of equal diameter marked B and 0. 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 slide-
screw wheel D,
and so moves the
slide (say from
the Head Stock
of the Lathe).
On the other
hand, when the
lever E is ele-
vated in position
E", wheel B is
taken out of gear
with A, while C
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 communi-
cation 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 bear-
ing. This is occasioned in most cases by some accidental change




406 INVENTIONS AND CONTRIVANCES. CIIRON. LIST.

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 res-
pective axes. This arrangement consisted in giving to the
exterior of the bearing a spJierical 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 foundry 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



CHRON. LIST. INVENTIONS AND CONTRIVANCES. 407

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 accom-
plished 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-rani of 2000 tons. I said, in a letter to
the Times, " As the grand object of naval warfare is the des-
truction 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." 1

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. 2 In June 1870, I received a letter from Sir E.

1 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 lacking of the plates, which, be it ever so thick, would yield to
the cramming blow of a moderate -sized Ram.

2 The following is the letter of General Sir John Burgoyne :

WAR OFFICE, PALL MALL,

LONDON, Sth 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



408 INVENTIONS AND CONTRIVANCES. CHRON. LIST.

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-matured 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 Van-
guard 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.

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 sub-
stantial 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



CHROX. LIST. INVENTIONS AND CONTRIVANCES.



409



1839. Invention of the Floating Mortar or Torpedo Ram.
For particulars and details, see Report of Torpedo Committee.

1839. A Double- faced W 'edge-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. 1 The result was my contrivance of a double-faced

1 At a meeting of the Institution of Civil Engineers, May 23, 1883,
when various papers were read on Waterworks, Mr. H. J. Marten
observed in the course of the discussion : " It has been stated in Mr.



410 INVENTIONS AND CONTRIVANCES. CHRON. LIST.

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 mo|t effective manner.

Mr. Wicks teed 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.

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 bo 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 con-
versation 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.



CHRON. LIST. INVENTIONS AND CONTRIVANCES.



411



1839. A Hydraulic Mattress Press, capable of exerting a pres-
sure of Twenty thousand tons.

Being under the impression that there are many processes in
the manufacturing arts, in which a perfectly controllable com-
pressing 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 desider-




atum. 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



412 INVENTIONS AND CONTRIVANCES. CHIION. LIST.

ordinary hydraulic press. The Hydraulic Mattress consists of a
square or circular water-tight vessel or flat bag formed of J-inch
thick iron or steel plates securely riveted together ; its dimen-
sions 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.

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 avail-
able 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 manu-
facturing 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 con-
struction 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 accumu-
lator, 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



Online LibraryJames NasmythJames Nasmyth, engineer; an autobiography → online text (page 33 of 37)