"When the strife is fierce, the warfare long,Steals on the ear the distant triumph-song,And hearts are brave again, and arms are strong."
"When the strife is fierce, the warfare long,Steals on the ear the distant triumph-song,And hearts are brave again, and arms are strong."
"When the strife is fierce, the warfare long,
Steals on the ear the distant triumph-song,
And hearts are brave again, and arms are strong."
Dimly distant though the final victory might seem, fierce and protracted though the strife,England continued unflinchingly pouring forth her bravest and her best, while she herself, with a determination grim and set, was of a truth turning "to swords her ploughshares," for experience had taught her that the Prussian was born not only a brute but a bully, and that the only way to deal with bullies was to hit them back, to keep on hitting until they were down, and once down to keep them there and prevent them from getting on their feet again.
But the maxim that "hesitation and half-measures ruin everything in war" had never been lost upon the "Great General Staff of (German) Imperial Supermen," who it might be opined had probably forgotten more in the gentle art of preparation for war than we ever set ourselves to learn. Gas shells, incendiary shells, tear shells, liquid fire, clouds of poison gas, aerial torpedoes, floating mines, submarines, mystery long-range guns, such were a few of the more obvious and less humanly unspeakable horrors in which the common enemy had specialised. Taken unawares, the question consequentially arose "How to hit them back?" Man for man, fist for fist, we were sure of giving as good as we received, and better.
"In bravery the French and English soldiers are the only ones to be compared with the Russians," was the verdict of Napoleon. Bravery, however, whilst being undoubtedly magnificent, is, on the other hand, in modern warfare liable to become a constraining source of suicide unless backed by commensurate means both of offenceand of defence. "The machine," as Mr. Lloyd George pointed out, when reviewing on December 20th, 1915, the progress of events of the preceding months, "the machine is essential to defend positions of peril, and it saves life, because the more machinery you have for defence, the more thinly you can hold the line. On the other hand it means fewer losses in attacking positions of peril, because it demolishes machine-gun emplacements, tears up barbed wire, destroys trenches." Again, "What we stint in material we squander in life."
How criminal had been the lack both of prevision and of provision in regard to meeting possible contingencies may be gathered from the fact that on March 15th, 1906, Major Seely, M.P., in the House of Commons, in moving a reduction in the Army Estimates (estimates which at that time did not exceed the modest sum of sixty millions per annum), said, "We could not afford to continue the present establishment, for the House would not grant the money, and the country would not provide the men."
The folly of it all was coming home to us with a vengeance. Proportionate to the former mean and niggardly "cheese-paring" was the resultant appalling rate at which life was now being squandered. "We were short of all kinds of military weapons," Mr. Lloyd George was forced to confess, "but the lack of high-explosive shell was paralysing"; then as if in condonation of all former sins of omission, "we believe that what is being done now to providea supply of munitions equal to all possible requirements will astonish the world when it becomes known."
In this respect, therefore, it is, perhaps, not unnatural that interest of a widespread nature should centre round Crewe, in virtue of the quota of munitions which she, albeit unobtrusively, contributed to the "world's astonishment"; indeed a certain sense of bewilderment not untinged with pride cannot fail to supervene in the minds of that vast section of the community, to wit the travelling public, and in particular the great North-Western-loving public, when, the official veil of secrecy being drawn aside, the mental faculty is free to note and to assimilate the degree of resourcefulness, the versatility of the locomotive engineer.
There is no concealing the fact that "the place acquired by machinery in the arts of peace in the nineteenth century has been won by machinery in the grim art of war in the twentieth century," but the anomaly was strange indeed when Crewe, essentially the cradle of what may perhaps be termed thehaute noblesseof locomotive progeny, bowing to the dictates of stern necessity, extensively adapted her domain to the novel effort of high-explosive shell production.
Manifold and great as are the instances which may be cited as evidence of the strides made during the last decade in engineering science, no other branch of that science has surely ever made appeal more alluring alike to schoolboyas to popular imagination, than that embodied in the modern British locomotive. Who in the course of his travel experience has not happened at that "Mecca" of railway bustle and romance, "Euston," the epic terminus of Britain's premier line, and focussing with his eye the hazy limit of a far-receding platform, has not traced the tapering profile of some distant-bound express, marvelling the while that, harnessed on ahead, should be pent up a force eager, impatient, yet withal so mighty that of a sudden, subservient to its call, this elongated span of motionless inertia laden with living freight should smoothly glide away, and gathering momentum on its path with ceaseless rhythm, ever along, along and along, sweep towards the far elusive line of the horizon? Yet this, in plain prosaic English, was the ennobling vista opened through peaceful years of patient toil and perseverance to the public ken, and dull must be the mind which contemplates unmoved that splendid emblem of the locomotive world, the awe-inspiring "Claughton" of that ilk, noble of mien and black of tint, with breast-plate red, toying with trains the equal of 400 tons and more, ticking aside the minutes and the miles alike.
Patriot"Patriot."—A Typical Example of the "Claughton" Class of 6 feet 6 inch, Six Wheels Coupled Express Passenger Engine with Superheated Boiler; Four h.p. Cylinders, 15-3/4 inch Bore × 26 inch Stroke; Boiler Pressure, 175 lbs. per sq. inch; Maximum Tractive Force, 24,130 lbs.; Weight of Engine and Tender in Working Order, 117 tons.[To face p. 99.
"Patriot."—A Typical Example of the "Claughton" Class of 6 feet 6 inch, Six Wheels Coupled Express Passenger Engine with Superheated Boiler; Four h.p. Cylinders, 15-3/4 inch Bore × 26 inch Stroke; Boiler Pressure, 175 lbs. per sq. inch; Maximum Tractive Force, 24,130 lbs.; Weight of Engine and Tender in Working Order, 117 tons.
[To face p. 99.
Figuratively speaking, Crewe may perhaps be referred to as the "spill" on which the face of the London and North-Western compass pivots; the four points, north, south, east, and west, extending respectively to Carlisle, London, Leeds and Holyhead; but familiar as are the scenes of everyday activity throughout theentire length and breadth of the Company's system, foggy, for the most part, are the notions as to the phenomenal whirl of industrial enterprise daily in progress within the precincts of Crewe Works.
Yet in these great engine Works (so menacing and unprecedented were the exigencies created by this voracious war), 'midst all the multifarious machinery and up-to-date appliances whereby is fashioned and evolved in all its amazing detail that complex piece of mechanism, the very essence of railroad itinerancy, the modern locomotive, was improvised with a speed approximating that of the mushroom which springs up in the night, a model and comprehensive plant, correlative with the multiform processes involved in the manufacture of that swift harbinger of death, the high-explosive shell, and its complement of grim appurtenances. How paralysing was the lack of these shells may be gathered from the fact that4"in the month of May (1915), when the Germans were turning out 250,000 shells a day, most of them high-explosive, we were turning out 2500 a day in high explosive and 13,000 in shrapnel." This gentle reminder to a lethargic House did actually (so we are told) evoke cries of "Oh," which latent degree of enthusiasm cannot be considered exactly vulgar or ultra ebullient, when side by side with so depressing a situation at home we endeavour to grasp the staggering figures as set forth in the following French official statement:—"Our artillery tothe north of Arras fired in twenty-four consecutive hours 300,000 shells, that is to say, very nearly as many shells as were fired by the entire French artillery in the Franco-Prussian War of 1870-71. The weight of these 300,000 shells can be put at 4,500,000 kilos; or nearly 4435 tons. In other words, more than 300 large trucks were required for carrying them by rail, or roughly half a dozen complete goods trains; by road this would have meant 4000 waggons, each with a team of six horses. The monetary value of these projectiles may be put at something like £374,800."
Prior to the summer of 1914, a shell, if not exactly an unknown quantity, was at any rate one of these obvious, even if somewhat curious things that might conceivably (in fact probably did) claim a certain amount of attention from that rather spoilt and very exclusive little clique, the professional army people. One read in the papers, too, from time to time, that the Navy (that immensely popular though slightly enigmatic asset of the Empire) was indulging in a little target practice somewhere out at sea; this would mean the firing of a few projectiles; but that was as it should be; we all liked the comfortable assurance that we could "sleep quietly in our beds;"5with an innate and justifiable sense of pride we liked, when occasion permitted, solemnly to stand up and join in the refrain "Britannia, rule the waves."
Latterly, however, the "shell" has acquiredso widespread a degree of prominence, proportionate to the toll of human life and of material damage that it has exacted, it has become in effect so commonplace an object, hackneyed as the very chimney-pots of a jerry-built row of houses, that a word of apology should perhaps be prefaced to any additional allusion to a subject already so often cited, which might otherwise and pardonably be regarded as superfluous.
Before diving, however, into any details as to the methods of manufacture, it may be interesting to pause for a few moments and to inquire into the nature of the mysterious movements of the shell when, deposited by the artilleryman with tender and loving care safely and securely within the breech of his gun, it flies away, the unerring intermediary between him and the hated foe of an argument deadly and convincing.
Our gunner experts (armchair no doubt as well as professional) will, of course, tell us that the flight of a shell is gyroscopic, this possibly in lucid contradistinction from that of the convex-shaped boomerang, which, according to reliable information, is gifted with the graceful, albeit inconvenient, art of returning to its original point of departure. The shell, however, ere it quits the muzzle of the gun, thanks to what is known as the rifling or grooving of the bore of the gun, thanks, too, to the action of that indispensable little adjunct familiarly known as the copper band, is imparted with the vigorous twist, andonce launched in mid-air spins round its longitudinal axis, undeterred, like the gyroscope, either by force of gravity or by atmospheric pressure.
This longitudinal spin is rendered eminently desirable, in fact imperative, for various reasons, of which length and explosive capacity of the projectile, accuracy in flight, diminished air-resistance in proportion to weight, and finally range, may be quoted as the more obvious desiderata.
The old ancestral cannon-ball, fired as it was from a smooth-bore gun, had no means of acquiring this sudden longitudinal twist, and no sooner clear of the muzzle, it found itself involved in the performance of antics whimsical and capricious, turning over and over on its transverse axis, head over heels, side slipping, looping the loop.
Again, the cannon-ball, being round, was limited in size to the bore of the gun, so that in addition to the disadvantage just mentioned of possessing no definite material degree of accuracy whilst on its headlong course through the air, it offered the further disadvantage of containing but a comparatively small explosive charge, and the air-resistance it afforded in proportion to its weight affected adversely, and in marked degree as compared with the modern longitudinal shell, its range and potential destructive energy.
Reverting then to the modern projectile, and taking as a suitably illustrative example the 6-inch high-explosive shell (for it was on this particular type that Crewe was asked to concentrate),bearing always in mind, too, that the modern gun is rifled or grooved and that the effect of this grooving is to impart a vigorous longitudinal twist or spin to the shell as it flies away, making it gyroscopic and almost uniformly accurate, we notice that the length of this shell is eighteen inches, thus exceeding the diameter in the proportion of three to one, whence it becomes obvious that the capacity available for explosive charge is proportionately greater than that of a cannon-ball of the same diameter.
We next find that in place of the rounded wind-resisting surface of the cannon-ball, the front end of the modern shell is pointed like a pencil, the atmospheric resistance being in this way reduced to a minimum. Decrease of wind-resistance naturally spells increase of range, and in this connection tests have in the past been carried out with shells having their bases as well as their noses pointed with a view to obviating the vacuum which is necessarily created by the usual flat base. A cigar-shaped shell, however, never proved satisfactory, for like the Rugby football it was decidedly wobbly in mid-air.
How requisite was a superlative degree of accuracy and consequently of skill in the manufacture of the modern high-explosive projectile may, to some extent, be gathered from these briefly stated considerations, and will become more apparent still when we come to glance at the series of component parts of which the whole is built up.
Premature explosions, involving loss of lifeamongst the gun-crew, the wrecking of the gun itself, not to mention resultant immunity from dismemberment of those previously destined to be the recipients of this unique form of greeting, areprimâ faciecontingencies to be guarded against; thus, owing to the sudden stresses to which a shell is subjected on the firing of the propellent charge whereby inertia becomes transmuted into velocity both forward and rotary, the steel of which the shell is made must be of such tensile strength that not only will the base-end withstand this transmutation, but the walls of the shell must be capable of overcoming the inertia of the front end of the shell, otherwise they will collapse, and a "premature" will be the immediate outcome.
An output of steel adequate for all munition purposes was already a problem sufficiently acute, and there were genuinely orthodox reasons why the home output, in particular, should be maintained at as high a level as possible. For one thing, it was eminently desirable that America should keep supplied our Allies who were less well equipped in "industrial and engineering resources than ourselves." "By home manufacture," too, "we had saved in the course of a single year something which is equal to 6d.or 7d.in the pound of income tax in the metal market alone." Besides "when you order a very considerable quantity of war material abroad, there is always a difficulty which arises with regard to the exchanges and the gold supply." There was also "the difficulty that you have not the samecontrol over the manufacturers of material abroad as you have got here" [Mr. Lloyd George, House of Commons, December 20th, 1915].
Influenced by considerations such as these, Mr. Cooke undertook not merely to machinein totoa given quantity per month of rough shell forgings, but proffered the extensive steel-making plant in Crewe Works, comprising several furnaces of 20 and 30-ton capacity, both for the supply of steel requisite for the initial manufacture of these rough forgings, and if desired, for a further output of steel wherewith to supply forgings to other firms engaged exclusively in shell manufacture.
The output of 6-inch high-explosive shells from Crewe Works had, at the time of the Armistice, reached, approximately, a total of 100,000, and the corresponding weight of steel forgings may be estimated, approximately, at 6500 tons. Government specifications in regard to tensile strength and cold fracture tests were not unnaturally exacting in the extreme, and the casts obtained at Crewe came fully in these respects up to the standard ordained. But amazing though it may seem (so tightly can the reel of official red tape be wound), notwithstanding Mr. Cook's offer and ability to furnish this supply of special high-grade steel, further Government regulations to the number of seventeen and covering three pages of foolscap demanded the observance of formalities, petty and extraneous, designed solely for the purpose of securing the right of incursion within CreweWorks of every Smith, Jones, and Robinson who under the pseudonym of "Government Inspector," and as units of a hugely overstaffed officialdom, sought by hook and by crook any and every means wherewith to justify their overpaid existence.
"Nobody but managerial and supervising engineers can quite realise what a handicap these people have been upon efficient production," writes a student of bureaucracy in theMorning Post, April 21st, 1919. "How the engineering industry has survived in spite of it is almost a miracle; how it has produced in spite of it is quite a miracle. At one time the Ministry of Munitions could boast of no fewer than 27,000 officials, nearly all of whose positions might be reasonably defined as "jobs." There were inspectors and inspectors of inspectors, super-inspectors, and inspector-generals, munition area dilution officers, munition area recruiting officers, recruitment complaints officers, and committees, directors, sub-directors, information bureaux, with all the usual paraphernalia; officials with and without designation, priority officials whose duties were as nebulous as their qualifications, besides an unnumbered crowd of arrogant but grossly inexpert experts. It is a splendid tribute to the industry that it triumphed over this deadly deterrent and redeemed its obligation to the nation under so cruel and undeserved a burden."
How Crewe Works survived in spite of this "handicap," this "deadly deterrent," is explainedby the fact that Mr. Cooke would have none of these things; in fact, sooner than conform to the caprice and tyranny of these "inexpert experts" from without, he very promptly withdrew his offer of steel manufacture, politely but firmly consigning "Major MacMarkfour" and "Captain Fitzgrazefuse" elsewhere, their correspondence to the nearest wastepaper basket; a friendly chat with the late Sir F. Donaldson, then Director of Army Ordnance at Woolwich, sufficing to make it clear that at Crewe everything was strictly "above board," and that the little entourage of professional experts within justified the full and complete confidence which he, their chief, reposed in them.
Not a few of the smaller engineering firms up and down the country, faced with previously unconsidered problems created by the unlooked-for transition from peace to war conditions, welcomed the call for shells and yet more shells, as a ray of sunshine peeping from out the lowering clouds of commercial stagnation. Hardly appreciating the fact that a shell's a shell for a' that, and approaching the task with a flippant disdain, akin to that of "selling seashells upon the seashore," some of these good people, ostensibly patriotic and avowedly disinterested, were soon asking themselves whether after all they had not bitten off as much as, if not actually more than, they could reasonably chew. The requisite degree of perfection in material, and of accuracy in machining, was at the outset a sore puzzle to the many who had never seena field-battery in action, who had never inquired as to the why and wherefore of the flight of a shell, who, by virtue of their exemption from military service, never had occasion to congratulate themselves personally on the subtle and unfailing precision of a creeping "barrage"; and great was the vexation of spirit, many the hours thrown away, legion the shells definitely consigned to the scrap-heap (or perhaps at best set aside pending some seemingly trifling rectification), ere aspirants to this novel and exacting sphere of machine-shop art attained anything approaching the acmé of perfection.
"It is better," wrote Napoleon, "to have no artillery at all than a bad artillery that endangers the lives of men and the honour of the nation," and selecting this fundamental principle as a basis on which to build the fabric of his excursion into the then untravelled paths of shell manufacture, Mr. Cooke made arrangements at the very outset for his leading representative of the machine-tool department to visit Woolwich, for the purpose, not only of acquiring first-hand knowledge as to the most approved Government methods of producing shells, but of making detailed dimensioned sketches from which to manufacture, in the Company's own tool department at Crewe, the multifarious gauges, or instruments, designed to verify in the most minute manner imaginable the diverse form of the shell.
The consecutive operations through which the shell passes number some thirty all told, andfor each separate operation separate gauges are required.
As emphasising not merely the delicacy of these all-important little instruments, but the delicate proposition "up against" which he found himself in his endeavour to discover firms who were capable of their manufacture, Mr. Lloyd George confessed that "we found that some of the shortage (of shells), if not a good deal of it, was due to the fact that, although you turn out shell bodies in very considerable numbers, you were short of some particular component which was essential before you could complete the shell. It might be a fuse, it might be a gauge. There was always some one thing of which you had a shortage!" Evidently gauges were a source of considerable anxiety because "we therefore had to set up two or three national factories in order to increase the supply of these components."
By already possessing the necessary machinery for, as well as considerable experience in, the art of gauge-making, Crewe was in a position to ease very materially the burden of those Government departments, those newly created "national factories" directly responsible for the manufacture and the issue of gauges in quantities sufficient to meet all demands, having merely to submit on completion any inspecting gauges to the National Physical Laboratory at Teddington for testing and stamping, prior to putting them into commission in the Works. Further, Mr. Cooke, as a member of a "strong committeeof machine-tool makers" who were then "sitting constantly at Armament Buildings in London," was specially qualified, in view of his inside technical knowledge and practical experience, to assist in "directing the operations of the whole of the machine-tool manufacturers of the kingdom"; and finally, as Mr. Lloyd George went on to say, "the result of all this" was "to increase very considerably not merely the output of shells, but also the power at the disposal of the nation at short notice to turn out even more than we have ordered if the emergency demands" (TheTimes, July 29th, 1915).
The rough forging of a shell body, rolled and pressed to suitable dimensions from a steel billet, is an uncouth-looking object, resembling as much as anything one of those upright earthenware umbrella-stands to be found in any cheap furnishing store; and with a view to licking it into shape, to turning it as quickly as possible into the smoothly finished article it was destined to become, Mr. Cooke's representative, on his return from Woolwich, having, as a preliminary, set in motion the machinery necessary for a supply of gauges, forthwith proceeded to improvise a further series of machines and tools, calculating the nature and number required for a given output of shells per month, and mapping out a plan whereby the various operations should follow one another from start to finish in correct and regular sequence. How important is the strict adherence to a regular sequence of operationsis borne out by the fact that a shell might easily be ruined in the event of any operation being performed out of its turn. A convenient and suitablelocalein which to lay out this shell-manufacturing plant was found available in a previously unoccupied extension of the new fitting shop; and as in the case of fuse manufacture at the old works fitting shop, so in the present instance, members of the fair sex were destined to figure prominently—a little band of neatly attired novices, some 150 strong, speedily responding to the call, and ranging themselves under the immediate supervision of a suitable quorum of expert mechanics of the sterner sex.
6-inch Shell Manufacture6-inch Shell Manufacture in the New Fitting Shop, Crewe Works.[To face p. 112.
6-inch Shell Manufacture in the New Fitting Shop, Crewe Works.
[To face p. 112.
A multiple cutter-milling machine, formerly habituated to the peace-time art of facing locomotive cylinders, suddenly found itself saddled with a row of a dozen shell forgings, the open ends of which it faced to a correct distance from the inside of the base. Thenceforward, engine and turret-lathes deftly manipulated by our little friends of the fair element bore the onus of the succeeding operations.
Ordinary engine lathes were eminently suitable for operations such as centring, rough and finished turning, grooving and external blending and turning copper bands. Then, thanks to the facility with which the various tools can be swung round in the lathe-turret and brought to bear on the work, turret-lathes were employed on operations such as rough and finished boring, internal blending, recessing and facing.
Rough turning on a fluted mandrel, rough and finished boring, and internal blending, in a concentric chuck secured to the face-plate of the lathe, are operations quickly disposed of.
"Blending," needless to say, produces in the mind an impression of smoothness and of harmony: smoothness unscored, that is, of the walls and base; harmony complete between the two, and indispensable.
Into the finished and concentric bore of our projectile is now forced a cleverly and home-designed expanding mandrel, a taper mandrel in fact, which expands a hollow (and again concentric) bush, and on this the base is centred. Transferred to an adjacent engine-lathe the shell is fixed on a shorter three-bush expanding mandrel, and turned to the correct and finished diameter. Removed to a turret-lathe, a slight operation of counter-boring the mouth is performed; this is necessary, as medical practitioners may be astonished to learn, for the purpose of receiving the nose. The mouth is also faced, and screwed, but screwing is effected on another instrument of torture, styled a thread-milling machine; so prior to lifting the shell from the turret-lathe a recess is cut in the far cavity of the mouth, this forming a clearance for the thread-milling tool. The turret of the lathe having no transverse travel, an ingenious little tool was designed and fixed into the turret-head by means of which a transverse travel, actuated by a hand-rachet and sufficient for the required depth of the recess, was obtained.
Anything which is at all conducive towards the saving of time, especially in war, isipso factoa device of the utmost strategic and economic value. "Ask anything of me but time," once said Napoleon, "it is the one thing I cannot give you." So, in the case of our thread-milling machine, the saving of time effected is considerable. The shell is as incomplete without the screw-thread in its mouth, as it is without its nose; the thread has to be cut somehow; and by the employment of a milling-machine and thread-cutter the job can be done in about ten minutes as against an hour or more if done in an ordinary screw-cutting lathe.
Having recourse once again to an engine-lathe, we attach a "form" (or guide) plate to the slide-rest, to the profile of which the nose and shell-body together are blended externally. As we are now nearing completion, the next item on the programme is to see how we stand for weight, and in the event of the shell being a trifle on the heavy side, we either take a light cut off, reducing ever so slightly the diameter, or else we shorten the base. There remain now the base-plate and the copper band to complete the whole; the former is either screwed or slipped with a plain circumference into a recess in the base, riveted over with a compressed air riveter, and faced to the required thickness; the latter is pressed hydraulically into a groove, then turned and grooved to the required diameter. A kind of miniature Turkish bath now awaits the long-suffering object of our commiseration, inwhich it is steamed and cleaned, then placed nose downwards over a tank. In this unenviable position a stream of varnish is generously sprayed with a hand pump up its inside. Thereafter it reposes in an adjacent chamber or stove until the varnish is thoroughly dried and baked; whence emerging, a pneumatic tapping machine is waiting to clear the varnish from the thread of its nose. It is then "boarded" both in regard to weight and overall dimensions, and if passed "A1" by the inspector proceeds into bond, where it remains until "called up," "reporting" at a filling factory, and in due course being "drafted over-seas."
Prior to quitting the workshop's busy hum and reverting with our mind's eye to the "battle's magnificently stern array," where we may compare to further, if superficial, purpose the projectile and its mathematically proportioned features with the somewhat violent form of gymnastic exercise in which it is about to delight, a word or two in reference to the evolution of the copper band may not be held amiss, in view of the importantrôleit plays relatively to the shell as a whole. The process by which these copper bands or discs were evolved was unique, and inasmuch as it was possible to effect a considerable economy by the evolution of three separate and distinct bands from one original sheet or square of copper, Crewe became responsible not only for the bands components of the 6-inch shell, on the manufacture of which she was exclusively concentrating her endeavours,but was able concurrently to produce for other firms further bands components of both 8-inch and 4·5-inch projectiles.
Equally with the fuse or gauge, the copper band ranks as one of those "particular components which are essential before you can complete the shell," and in order to preclude in so far as lay in his power to do so the possibility of any shortage of this particular component, Mr. Cooke put in hand and had completed within a fortnight from the date of commencement an entirely new hydraulic press having a capacity of 130 tons and a working pressure of 2000 lbs per square inch, by means of which copper cups were pressed out to approximately 700 per day, and from these cups were cut and turned bands of different diameters according to the size of shell for which they were required; the total number of copper bands thus manufactured at Crewe at the time of the Armistice being upwards of 700,000.
The method was simple when once evolved. The 8-inch band being of the largest diameter of the three was the first to be dealt with, then the 6-inch and finally the 4·5-inch. A piece of flat, square copper plate was first dished in the press by means of a solid punch, to the shape of a shallow bowl; annealed, it was pressed a little deeper; annealed again, the process was repeated a third time, but deeper still, the dish becoming a cup; and in order to obviate the drawback of the walls of the cup clinging to the circumference of the solid punch,a cleverly contrived split and collapsible punch was introduced, that is to say a punch which, on being pressed downwards, was expanded by a taper wedge to the full diameter required, and which, on being withdrawn, collapsed or shrank inwardly in proportion as the taper wedge preceded and automatically withdrew the expanded and circular sides, the latter disengaging simultaneously from the walls of the cup.
Transferred to the fitting shop, a band or disc 8-inch diameter was turned and cut off from the cup, the latter returning to the press, where through the medium of similar punches of requisite and correspondingly smaller diameters further operations resulted in the evolution of cups from which were turned 6-inch and 4·5-inch bands respectively and in sequence.
The proportionate number of bands cut from the three sizes of cups were, as a general rule, three from the smallest or 4·5-inch, eight from the intermediate or 6-inch, and one only from the largest or 8-inch, and it was in some measure due to these circumstances, due, no doubt, too, to a certain difficulty in obtaining delivery of copper sheets in sufficient quantities, that for the purpose of increasing the output of 8-inch bands and of maintaining this output on a level with that of the two smaller sizes, recourse was had to the brass foundry, where it was considered practicable to cast the bands, especially in view of the amount of copper scrap of both shearings and turnings that was available for melting-down purposes.
A certain amount of preliminary experimental work was perforce entailed, both for ensuring that the band, when cast, should exhibit an estimated degree of shrinkage (for the greater the shrinkage the sounder the casting, a shrinkage of 1/4 inch being usually accepted as a minimum), and that the metal should be capable of withstanding certain specified Government tests, the one condition, of course, being contingent on the other. Tests which were actually made proved wholly satisfactory, the average results being an elastic limit of 7·5 tons per square inch, an elongation of 45 per cent. on two inches, and finally a breaking stress of 14·5 tons.
De-oxidisation, that is to say the process of removing oxygen from the metal for the purpose of obtaining castings that were sound, free of blow-holes and of oxide of copper, was effected by mixing a small percentage of phosphor-copper with the molten copper in the crucible.
Boron-copper was also tried as a de-oxidiser, but no real advantage was noticeable. Comparative tests, too, were made for the purpose of ascertaining the percentage of loss of copper when melted in crucibles and again in a reverberatory furnace. The former process resulted in a loss not exceeding 3/4 or 75 per cent.; whereas the latter was responsible for a 7 per cent. loss. Any saving which came within the meaning of the word "economy" as completely removed and distinct from that of "parsimony" was a precept not merely preached but extensivelypractised throughout the locomotive department at Crewe, and as an illustrative instance of this praiseworthy, and therefore patriotic, policy the casting of copper bands may be cited.
Although cheaper and possibly less reliable methods of producing copper bands may have conceivably come into being during the final stages of the war, it was obvious to even the least well-informed in such matters that, provided a mixture could be obtained whereby the metal could be relied upon to pass the Government tests, the process of pouring molten copper from a crucible into a sand-cored cast-iron chill was likely to be at any rate cheaper than that involving the employment of presses, rolls, shears, and punches.
On comparing the estimated cost of manufacturing copper bands by the pressing and casting processes respectively, a difference of one shilling per finished band was shown in favour of the latter system; and although it may seem a mere bagatelle, a drop in the ocean of squandered millions, to those who not merely are encouraged, but who encourage others, in the art of reckless and profligate extravagance when handling the public purse, this modest shilling per copper band saved represented an aggregate of £1750, a sum not altogether to be sneezed at when we consider that the value of the 35,000 bands cast in Crewe Works was but an infinitesimal fraction of the total munition expenditure during the war.
We are told that "the use of travelling is to regulate imagination by reality, and instead ofthinking how things may be, to see them as they are." Hence it has been, we may confidently aver, for the purpose of seeing things as they are that we have availed ourselves of this opportunity to fathom in some measure for ourselves the abstruse art of shell-manufacture as practised in Crewe Works. The imagination, however morbid and obtuse, can hardly fail to be stirred when pondering the rotund and rudimentary profile of the rough shell-forging lying with all its latent possibilities, recumbent in the lathe; ultimately in its finished formc'est cela,6the shell we meditate,qui va nous débarrasser des Prussiens; thanks now to that generous impulse which prompts our gallant gunner-men, good fellows all, possessed of "mildest manners with the bravest mind," to unravel for us the all-absorbing mysteries of that sphere of "war's glorious art" in which they themselves excel, reality will regulate our questioning imagination as we follow them to the dim seclusion of some cleverly camouflaged gun-emplacement.
We have already seen that the motion of a shell is rotary as well as forward, this rotary motion being brought about by the joint instrumentality of the grooving of the bore of the gun and of the copper band on the shell.
Another and very important function performed by the copper band approximates to that of the piston-ring of a locomotive cylinder, which prevents the passage of steam from one side ofthe piston to the other. Concomitantly, the copper band, turned a fit in the bore of the gun and jammed into the rifling, is designed to obstruct the passage of the propellent gases beyond the base-end of the shell; these gases are naturally imbued with a habit or hobby of gnawing away, or eroding, any metal surfaces with which they can come into contact, so that the further they can penetrate up the bore of the gun, the more material damage that will ensue, and the rifling becomes proportionately erased or eaten away. Further, owing to the fact that the degree of heat generated by the ignition of the propellent charge is obviously most intense in the area most adjacent to the base of the shell, erosion becomes patently more pronounced here than in other directions; consequently as the area in which the propellant gases are exploded increases, so the pressure exerted by these gases decreases, the net results of these considerations being loss of accuracy and of velocity.
Different civilised communities favour different kinds of explosives as a gentle means of attaining their ambitions, and these explosives may be solids, liquids, or gases. In this country picric acid (or, tri-nitro-phenol), and tri-nitro-toluene (or in its abbreviated and more easily pronounced form "T.N.T.") are the two kinds most extensively adopted for the filling of high-explosive shells. Owing, however, to certain unexplained caprices in which it is known to indulge, owing, too, to the fact that personsemployed on its manipulation have died from the effects of trotyl poisoning, T.N.T. is less extensively employed, in spite of certain known and obvious advantages which it possesses over picric acid.
Picric acid solidifies after being run in a molten condition into the shell, and every precaution has to be taken in order to prevent, during solidification, the formation of cavities, because the least tendency to friction that might occur due to the "setting back" of this hard explosive mass resultant on the sudden forward movement of the shell might easily give rise to a "premature." Herein we recognise the vital importance of wholly harmonious internal blending, absence of which might prove a further source of friction entailing imminent peril to ourselves as we stand beside the gun. Again, picric acid is ever seeking opportunities for combining with metal, whereby compounds of a nature most sensitive, and styled "picrates," are created, and of which the most sensitive is the lead-picrate. Hence we breathe a silent prayer that not only has the shell's inside been sprayed in the most efficacious and thorough manner possible, but that the composition of the varnish itself is entirely lead free.
Our wives, our families, our friends, we fain would turn to them as of a sudden a fresh suggestion, fraught with peril dire, creeps from out some hidden corner of our timorous mind.
On the firing of the propellent charge, the expanding gases, we are told, cause expansion ofthe gun, thereby simultaneously allowing proportionate expansion of the shell. We know already that erosion is most pronounced round the area within which the propellent charge is fired, that is to say, just at the commencement of the rifling of the bore; hence we see that in all probability the bore decreases gradually, even if imperceptibly, in the direction of the muzzle. We have, however, had experience of these varying and imperceptible degrees of graduation at Crewe, measuring them with our plus and minus gauges. What, therefore, if the shell, expanded in the commencement of the rifling, jams, or is momentarily checked, in its passage up the bore? A "premature"; for the pellet in the fuse is probably already free to jump forward against the detonating needle. These nightmare prematures! Thank goodness, after all, in one direction, at least, assurance has been rendered doubly sure; we used to wonder why all this fuss and trouble about a base-plate? Now we understand. Imperceptible must be our attribute again; metals are porous, imperceptibly so. Now imagine a sieve trellised with wires finely drawn as the threads of a spider's web, threads so closely woven and interlaced that only the most minute "teeny weeny" holes remain, a sieve in fact which though porous is not even transparent. Figuratively speaking this is the base of a shell-forging; a porous partition, the sole dividing line between the ignited propellent gases behind, and the high explosive burstingcharge within the shell; in other words, between ourselves and "kingdom come"; hence our supplementary or protecting plate, the grains of whose metal run crosswise to those of the shell-forging base. By this method of reinforcing the shell-base, the odds in favour of a "premature" due to the penetration of the propellent gases to the explosive charge are reduced to a further irreducible minimum.
The gun is, of course, designed to withstand the pressure within the breech and behind the shell, exerted by the firing of the propellent gases; this pressure naturally varies according to the size of the gun, and decreases proportionately as the shell shoots forward towards the muzzle with rapidly increasing velocity.
When, however, we come to consider the pressure exerted by the detonation of the high-explosive charge within the shell itself, and the velocity acquired by the resultant explosive gases, we are apt to fidget about a trifle uneasily in spite of our efforts to remain at least outwardly cool and nonchalant.
All the same, a matter of 300 tons per square inch, which is the pressure liable to be exerted by the detonation of an average charge contained within the high-explosive shell, can only be explained as "splitting"; and when our genial gunner-friends further assure us that 7000 metres or 21,000 feet per second is the velocity resulting from the detonation of "Trotyl," "staggering" is perhaps the most fitting epithet, and an American "Gee whiz" the only coherentsign of comprehension of which we are capable at the moment. For supposing a "premature" did chance to occur; well...! Mercifully enough perhaps for them and for their peace of mind, these intrepid individuals the gunners have little or no time, as a rule, to reflect upon the naked meaning of these figures and their attendant possibilities; for as Kipling has sung—