and boiler works, is run from one central station, of which two views
are given on Plate XLVIII., opposite. The electric generators occupy
one side of the power station, and the air compressors and hydraulic
pumps the other. Steam at 200 lb. pressure is supplied by one marine
cylindrical, and four Babcock and Wilcox water-tube, boilers, with
superheater, coal conveyors, and mechanical stokers.
[Illustration: Plate XLVIII. ELECTRIC GENERATORS IN THE POWER STATION.
HYDRAULIC PUMPS AND AIR COMPRESSORS IN THE POWER STATION.]
There are three electric generating sets, with a total capacity of
1200 kilowatts, the voltage being 240. They are illustrated on Plate
XLVIII., facing this page. The engines are of the high-speed, enclosed,
forced lubrication, condensing type. The current is distributed from a
switchboard in the power station by overhead mains, with three-way
distributing panels in the various departments. The motors, of which
there are about 130 in the shipbuilding department alone, are of the
two- and four-pole type, partly or entirely enclosed, and mostly of
10 to 20 electric horse-power. Arc lamps are used for lighting, but
the shops and offices are also illumined by 16 and 32 candle-power
incandescent lamps. Plugs are arranged at various points throughout the
yard for portable lights, and for connecting mains for lighting the
various ships while being completed in the docks.
Hydraulic power at 800 lb. pressure is generated by two high-pressure
pumps, with steam cylinders 15 in. in diameter, and rams 4 in. in
diameter. There are separate accumulators for each. The pressure pipes
are led underground throughout the Works to the various hydraulic tools
already referred to.
There are two air compressors for supplying power for the pneumatic
tools. The combined capacity is 1800 cubic feet of free air per minute.
Each has two steam cylinders 6 in. in diameter, working respectively
high- and low-pressure air cylinders 15-1/4 in. and 21-1/4 in. in
diameter, the stroke being 18 in. The hydraulic pumps and the air
compressors are illustrated on Plate XLVIII., facing page 104.
As we have already stated, part of the power generated in this station
is utilised at the engine works, to which we may now turn our attention.
[Illustration: decoration]
[Illustration: decoration]
The Engine and Boiler Works.
[Illustration: decoration]
Rapidity of construction has been characteristic of the engine and
boiler works of the Scotts to at least as great an extent as in the
shipbuilding yard. Several instances might be noted, beginning with six
blockade-runners, built in a very short period, in 1864, and fitted
with engines to give a speed of 12 knots at sea and 13-1/2 knots on
trial. A recent and striking instance is the construction of boilers
and engines for twenty of the passenger steamers built for traffic on
the Thames, to the order of the London County Council, and described on
pages 83 and 84, _ante_. The contract for this work was signed towards
the end of November, 1904, and work was commenced about the beginning
of December. The various parts of the engines were being machined and
finished during the month of January and the beginning of February,
1905; and all of the twenty sets of engines and boilers were completed
by the end of May. Another noteworthy case is the construction of the
machinery for the steamship _Fengtien_, described on page 80, _ante_.
Work was commenced on the machinery in the middle of January, and
finished about the end of April. The machinery was fitted in the ship
and ready for the trials on the 29th May. The total time taken from
the beginning of work was well under five months.[69]
[Illustration: Plate XLIX. VIEW IN MAIN MACHINE SHOP.]
The pattern shop, where all work originates, is fitted with the usual
pattern-making machinery, including a core-making machine.
The iron foundry, which was begun in 1790,[70] and around which the
large engineering establishment has since been raised step by step,
continues to do sound work. There are four cupolas, of a combined
capacity of about 20 tons, and cylinders up to 120 in. in diameter are
cast. These facts suggest the satisfactory character of the equipment.
The brass foundry is an equally important department, where first-class
work is done. There are fifty-two crucible pots in use, varying in
size up to 150 lb., and of a collective capacity of about 2 tons; also
an air furnace capable of producing at one heat 12 tons of metal, for
such heavy castings as are required for preparing shaft liners, large
sea chests for naval ships, etc. The strength of Admiralty gun metal
made in this foundry is up to 18 tons per square inch, with 30 per
cent. of elongation in a 2-in. length. The foundry is served by an
electrically-operated jib crane.
In the forge and smiths' shops a large amount of detail work is done,
in units ranging up to 3 tons in weight. The hammers vary up to 15 cwt.
power. A considerable amount of die-stamping is done in connection with
auxiliary engine forgings, etc. All paddle-wheels are made in this
department. The blast for the fires is got from an electrically-driven
fan.
The machine shop, which was one of the first constructed with a
completely glazed roof, occupies a site on a steep slope, one side
being formed by a heavy retaining wall, as shown in the engraving on
Plate XLIX., facing page 106. At the level of the top of the wall,
which is 25 ft. high, there is the light machine shop, while at the end
of the bay and over the annexe situated to the left of the engraving,
is the brass-finishing shop. There is a 2-ton hoist between the
erecting-shop floor and the galleries, so that no inconvenience, so far
as transport is concerned, is involved by this arrangement.
Originally a stream ran down the hill and over the site on which the
Works are located, and its waters have for many years been utilised
as a source of power. A special 24-in. inward-flow turbine works in
the conduit which conveys the water across the site, and this turbine
develops continuously 80 horse-power. This serves to drive some of
the machines in the boiler works. The turbine runs in parallel with
a compound vertical engine, which drives the shafts actuating the
groups of small machines in the engine shop. Many of the larger tools,
however, are electrically-driven by separate motors, the current being
transmitted from the central station already described.
The engravings on Plates XXXIX. and XLIX., facing pages 92 and 106
respectively, illustrate the main machine shop, which has a width of
60 ft., and, with the adjoining bay, accommodates some of the finest
marine engineering tools made. Perhaps the best indication of their
efficiency is the fact that three weeks suffice for the machining of
the parts of a complete set of engines to develop 2000 horse-power. The
shops are traversed by five overhead electric cranes, ranging up to 40
tons lifting capacity.
[Illustration: Plate L. VERTICAL PLANING MACHINE.]
[Illustration: MULTIPLE SPINDLE DRILLING MACHINE.]
[Illustration: Plate LI. SURFACE AND BORING LATHE.]
The leading dimensions and the principal work done by the more
important tools afford an idea of the extent of the equipment. There
are several planing and slotting machines, one of which is shown in
the engraving on Plate L., facing this page. There are two combined
machines, to plane 21 ft. and to slot 18 ft., used in connection
with the condensers, cylinders, large bearing frames and sole-plates
of engines, while two other smaller tools are devoted to finishing the
castings for bed-plates and columns. For machining eccentric-rod ends,
etc., there is a 24-in. slotter with a circular table. There are two
high-speed planers with two tool-boxes on the cross-slide, which take
in pieces 10 ft. by 5 ft. by 5 ft., and one to take work 12 ft. by 3
ft. by 3 ft.
In the driving of some of the heavier tools very good results have
been attained by the application of a reversible motor, which in one
case has dispensed with four belts, a pair of bevel wheels, and two
countershafts, reducing enormously the frictional waste, and enabling
higher speeds and quicker return strokes to be attained.[71]
For drilling work there are several large tools. Recently there has
just been fitted a multiple machine which, while primarily intended for
drilling the tube-holes in drums and water-pockets of Yarrow water-tube
boilers, is also utilised in connection with ordinary machine work.
This tool, of which an engraving is given on Plate L., facing page 108,
was manufactured by Messrs. Campbells and Hunter, Limited, Leeds. It
has a massive cross-slide carrying four saddles, movable by a powerful
screw, driven by spur-gearing and friction-clutch, controlled from one
of the saddles. The steel spindles are balanced, and have a special
self-acting, variable, rack-feed motion, as well as a quick vertical
motion by hand for rapidly adjusting the drill through the jig. Each
spindle can be operated independently. The table has a sliding motion,
directed by two straight screws coupled to the cross shaft and vertical
shaft, and is carried by a straight bed with three bearing surfaces.
This machine, which weighs 20 tons, is driven by a 30 brake-horse-power
electric motor.
There are two vertical boring mills used for cylinder work, one being
capable of boring up to 120 in. in diameter, and the other to 94 in.
in diameter. A combined boring and facing machine, with a table 4 ft.
square, is usefully employed on propeller bosses, valve-chests, small
cylinders, and built-up bed-plates, machine bearings, etc.
The installation of high-speed lathes is specially noteworthy. In
one, the face-plate can take in 12 ft. in diameter, and, as the
length of bed is 30 ft., it is useful for large surfacing work, as
well as for turning crankshafts of the larger sizes. There are two
12-in. double-geared lathes for surfacing and screw cutting. These are
self-acting, and the lengths of bed are 19 ft. and 12 ft. respectively.
For turning piston and connecting rods, two screw-cutting lathes of
16-1/4-in. centres are in use, the length of the bed being 22-1/2
ft. These have each a triple-gear headstock, and a chuck 48 in. in
diameter; with rack motion and slide-rest feeds. A 20-in. centre lathe,
with a bed 28 ft. 6 in. long, is fitted with two saddles and four
slide-rests for shaft liners, etc. Amongst others, there is a 27-in.
centre lathe for shafting, the bed being 36 ft. long.
One of the lathes is illustrated on Plate LI., adjoining page 109. This
is a 48-in. surfacing and boring lathe, by Messrs. John Lang and Sons,
Limited, Johnstone. The two new features introduced are the variable
speed drive and automatic speed-changing mechanism. The headstocks
can be used for single or triple gear, and are so arranged that, even
when running at the greatest speed, there is a reduction by gearing.
With this arrangement the lathes have greater power when turning
small diameters than when the belt is used driving direct to the main
spindle. The spindles, which are hollow, with hexagonal turrets, are
of crucible cast steel, and run in gun-metal bearings. By means of
the speed-changing mechanism, the cutting speed of the tool is kept
practically constant when surfacing. This means that any surface can be
finished off in about one-half of the time taken by a lathe having
the ordinary step-cone drive, where the workman will not change the
position of the belt while surfacing. The self-acting feed-motions are
positive.
[Illustration: Plate LII. BRASS FINISHING SHOP.]
Milling is adopted in many instances in preference to planing or
slotting, and this is especially so in connection with valve quadrants,
columns, faces, etc. For the first-named there is a large vertical
miller, and for the latter a horizontal tool with a vertical milling
apparatus. For grinding bolts, etc., a machine having a separate head
for grinding taps is used, the emery wheel being 18 in. in diameter and
1-1/2 in. broad.
A shop, now in course of construction, is to be specially laid out for
the manufacture of turbine machinery of the greatest power. It is to
be 285 ft. long, with a span of 60 ft. Heavy lifts will be taken by a
100-ton overhead crane, and ordinary work will be handled by a 40-ton
electric crane. The heavy machine tools, while specially chosen for
turbine work, are also adaptable for use in the manufacture of the
heaviest reciprocating machinery. The principal tools are large lathes
suitable for turbine rotors and crank-shafts; vertical boring machines
which may be utilised for work on cylinders as well as on turbine
casings; and a heavy planer, 10 ft. by 10 ft. by 25 ft. stroke. The
necessary small machine tools for turbine work will be put down in this
department, whence also some of the large tools will be removed from
the existing shops, so that it will be fully equipped for the purpose
intended.
The brass-finishing shop, which is illustrated on Plate LII., facing
page 110, serves both for ship and engine work. It has only recently
been laid out anew. The machines, according to the latest practice, are
arranged down each side of the shop, and the benches occupy the centre.
Each alternate bench is utilised for the material to be operated upon,
so that the working bench is not littered in a confused way, as is too
often the case. There are representative types of the best makes of
automatic tools, turret lathes, brass-finishers' lathes, and grinding
machines with specially large discs.
A considerable amount of work is done to limit gauge in all the shops
which we have described. This practice has been considerably developed
recently, and a specially equipped department has been organised,
where gauges, templates, and cutting tools are made. This department
is illustrated on Plate LIII., facing this page. A word may first be
said as to the significance of this new department. Where three or
four ships have engines of the same type, a set of jigs and templates
for the most important parts are at once made, so that a unit from
an engine in one ship may be fitted to an engine in another. This
simplifies the ordering of new parts, and greatly reduces the number of
spare items which have to be kept in store by the owners, in order that
repairs or refits may be effected at short notice.
For some time the Scotts have adopted this system, so that it was a
simple matter to enforce it in connection with the machinery of the
twenty Thames Steamers, and in recent naval work, where the practice
is being applied in an extended form. In the recent Admiralty work
every part of an engine is made interchangeable and identical with
the corresponding parts of other engines for the same type of ship,
although built in different parts of the country; and this fact
alone will indicate the extent and intricacy as well as the care
and degree of accuracy necessary. This standardisation to ensure
interchangeability has reached its highest exemplification in the
case of the machinery for the armoured cruiser _Defence_, of 27,000
indicated horse-power, to be completed in twenty-one months from the
placing of the order by the Admiralty.
[Illustration: Plate LIII. TOOL, GAUGE, TEMPLATE, AND JIG DEPARTMENT.]
Then, as regards the tool-making and fettling--the other branch of work
carried out in the tool room--it has been recognised that, to make
the cutting tools efficient, it is necessary to utilise the most
suitable steel for the tools working on various metals and alloys; and
the selection of the tool steel for each metal has been systematised by
the careful collation of data of actual work. In the manufacture of the
tools special appliances are used and will be referred to presently.
The workmen are encouraged to use only tools in sound condition. Each
machine-man in the shops has ten checks, and may borrow from the store
a corresponding number of tools, but these must be returned as soon as
possible for overhaul and re-grinding. The bonus system further induces
the men to ensure that their tools are in good condition.
The tool department is separate from the main structure, and in it
all jigs, templates, and gauges, as well as tools, are constructed.
Standard gauges, as well as limit gauges, are used, and both are
marked in metrical and English dimensions. The tool room is not only
carefully maintained at a regular temperature, in order to prevent the
templates and jigs from varying in the course of their manufacture,
but the appliances adopted have been selected so as to get the most
precise results. In connection with the manufacture of large boiler
taps, drill gauges, milling cutters, etc., a specially designed gas
furnace has been built, with a number of compartments which can be used
separately or collectively, according to the size of the tool being
made. The toolsmith's forge is on the down-draught principle, so that,
in addition to carrying off all smoke and dust, it tends to keep the
atmosphere pure.
Amongst the principal machines used in this tool-manufacturing
department is an 8-in. Whitworth self-acting, sliding-surfacing,
and screw-cutting lathe, with a backing-off and taper-turning
attachment. The milling, drilling, and grinding machines are all by
the best makers. A 10-ft. machine is used for making the comparative
measurements from existing standards. This machine, also of Whitworth
make, has a measuring screw in a fast headstock with a large dividing
wheel, one division of the latter representing 0.0001-in. in the end
movement of the spindle. All transverse and tensile testing of bars is
done in this department.
A check system is used in connection with the distribution of
templates, tools, drawings, etc., and a separate store in the centre of
the works is arranged for this purpose.
[Illustration: HYDRAULIC PLATE-BENDING MACHINE.]
As to the boiler works, the fact that in 1905 the production was
practically one boiler per week is, of itself, testimony to the nature
of the plant adopted. The main boiler shop, together with its yard, has
an area of 7000 square yards, and a height of 45 ft. to the crane rail,
and is served by five overhead electric cranes, ranging in lifting
power up to 100 tons, with numerous jib and other cranes associated
with the various machine tools.
[Illustration: Plate LIV. IN THE BOILER SHOP.]
The machine tools fitted in the boiler works are all of a very powerful
character; but only a few of these need here be referred to. There
is a 13-ft. gap hydraulic plate-bending machine, which is entirely
automatic in its action, and can be set to any radius to bend plates up
to 2 in. thick when cold. The flanging for the front and back plates
of boilers is done in an hydraulic machine, exerting a pressure of
over 160 tons. This machine has four rams, two of which act downwards,
one upwards, and the other horizontally. It is served by a special
hydraulic jib-crane, capable of lifting the heaviest plates. There are
also plate-edge planers and triple boring mills of corresponding power,
while the vertical rolls take in plates up to 10-ft. wide.
For the riveting of the boilers there is a 13-ft. gap hydraulic
riveting machine, capable of exerting a load on each rivet of 200
tons. The weight of this riveting machine alone is about 60 tons, and
it is served by an independent hydraulic jib-crane. All the valves in
connection with the crane and riveter are led to a common platform, so
that one man is able to manipulate the whole of the work.
There is also a large installation of special plant for the manufacture
of water-tube boilers, but it is scarcely necessary to describe this in
detail.
A large part of the boiler work, especially for warships, is
galvanised, and a special department has been organised for this
purpose. The tubes, in the first place, are thoroughly cleaned, then
placed in a zinc bath, and coated by electrolysis to the desired
extent; the object being to expose defects, as well as to protect the
tubes from corrosion during manufacture. The amount of work done is,
perhaps, the best indication of the equipment of this department, as
well as of the water-tube department; and this will be realised when it
is stated that over 24,000 tubes are required for the boilers of one
cruiser, and that six months suffices for their construction.
It would be possible to give other indications of the splendid
equipment of the Works, but enough has been said to show that
there is directed towards the realisation of the best work in all
departments--firstly, the advantages of accumulated experience,
carefully collated throughout two hundred years; secondly, the benefits
which the psychologists claim for hereditary influence--applicable
here not only through the proprietors, but also through many of the
workmen; and, thirdly, a sound progressive spirit, which recognises the
necessity for continual improvement in administration and design, and
in machine tools and methods of manufacture.
[Illustration: decoration]
FOOTNOTES:
[69] For further references to the rate of construction, see
_Engineering_, vol. lx., page 813, where it is noted that ten vessels,
aggregating 26,000 tons, were built for the China Navigation Company in
nine months.
[70] See page 22, _ante_.
[71] See _Engineering_, vol. lxxx., page 418.
PRINTED AT THE BEDFORD PRESS, 20 AND 21, BEDFORDBURY, STRAND, LONDON,
W.C.
End of Project Gutenberg's Two Centuries of Shipbuilding, by Various