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Note: This is a sub-section of 1881 Iron and Steel Institute
The party that selected the telegraph works at Charlton for inspection numbered about 250, and was received by Dr. C. W. Siemens, F.R.S., past President of the Institute, and the various heads of departments. After being most hospitably entertained at luncheon, the members were shown the various processes carried on in the manufacture of telegraph cables, &c.
For submarine cables the insulating material is gutta-percha, of which between 1000 and 2000 tons per annum are here used. The gutta-percha arrives at the works in lumps of the rough stalagmitic form into which the material consolidates after running from the tree. The first process in the preparation of the gutta-percha is to chop it into small pieces by means of a revolving disc fitted with oblique knives. The material is next boiled_ in vats, and it afterwards passed on to the "masticators." The masticator consists of a longitudinally ribbed roller, in section similar to a toothed pinion revolving within a concentric cylindrical case. The soft lump of gutta-percha, after being thoroughly worked by means of these machines, is placed in a cylinder, and forced by a piston through a strainer of fine wire gauze. Any small pieces of foreign matter are thus eliminated. Passed on to the "washer," it is again boiled, and at the same time subjected to the action of another ribbed roller of coarser pitch. The mass comes out in a pasty condition, and is poured on to an iron plate and allowed partially to set. It is next passed on to the rolling-mill, where it is rolled into sheets of about 3/16-inch in thickness, whence it passes into the cellars beneath, where it is stored for use.
The copper core of the cable is embedded in a solid cylindrical covering of the gutta-percha so prepared, by means of a machine specially designed by Messrs. Siemens, and the result, after their lengthened experience, is now so perfect that a flaw in the insulation, in the subsequent testing process, is rarely found. In this machine, the copper core is first heated by passing it through a tube operated on by a gas flame. It then enters a hole at the side of a box containing the gutta-percha coating in a plastic state. This box communicates with a cylinder fitted with a piston which is forced down by a screw, so that the gutta-percha is under severe pressure. The core passes out of the box at the opposite side to that at which it enters, the dies through which it makes its exit having a diameter equal to the outer diameter of the coating of gutta-percha to be put on. The wire, as it issues, is covered by the desired • coating, the gutta-percha being forced out with the core. The coated wire as it issues from the dies passes at once into water, which sets the gutta-percha hard. The 'insulated cores traverse a long trough well filled with iced water, and are then collected on drums. After the cores have been wound on drums, the insulation of each drum of core is tested at two standard temperatures and atmospheric pressure for several weeks, and finally by subjecting it to a hydrostatic pressure of about four tons to the inch, and passing an electric current through it, whilst under pressure, with a view to detecting, any possible leakage. After being tested, the core is transferred to the cable-sheathing department; and passes successively through the core-serving machines, where it is spirally served with yarn; thence to a tank of water, in order to give the insulation a further test; thence to the cable machine, where it is covered first with steel wire, then with a compound of tar and pitch, which is poured on at a temperature of 90° Cent., and then with successive layers of yarn wound each time in opposite directions, a layer of the pitch compound being interposed each time. The final layer of yarn is also covered with the tar and pitch compound. A stream of water is then poured over it in order to set the external coating. The finished cable ultimately passes on to the cable tanks, of which there are some twenty or more, and of which the largest are capable of holding some 600 knots. Here the cable is stored until it can be removed on board the ship which is to lay it.
All the wire used in the cable machines is carefully tested in a testing-shop to a certain weight strain, for elongation and for torsion strain. In the same shop apparatus is fitted for testing the yarn. The shore ends of the cable are made much thicker than the portions which are sunk in deep water to guard against injuries from the anchors of vessels and from other causes. There are some twenty tanks at the works, situated between the cable floors, and each capable of holding from 100 to 600 knots of cable. There are thirteen cable-sheathing machines at work. Great precaution is taken in testing electrically each length of cable as it is manufactured. The instruments used for measuring the electrical condition of the cables are the so-called electrical balances, composed of a series of resistance coils and the reflecting galvanometer of Sir W. Thomson, which is used for measuring the insulation resistance. This instrument is so sensitive that the smallest currents are indicated. The astatic needles move between two pairs of coils, and when a current passes through the coils the needle is deflected according to the strength of the current. In order to make the indications visible, the magnet of the needle is provided with a small mirror, upon which light falls from a lamp placed at a suitable distance. The light reflected from the mirror falls on a scale where the angle of deflection is made to indicate the strength of the current. An improvement in the scale of the galvanometer has been recently effected by Mr. Jacob, the principal of the testing department, by which one lamp is made to serve for two instruments. The light falls through a piano convex lens on a mirror at an angle of 45°, whence it is reflected upon the mirror off the galvanometer, and thence back upon a plain mirror, which throws the image on a transparent scale. A long beam is thus reflected in a small compass, and the effect is to magnify the deflection.
In another portion of the works india-rubber is passed through the various stages of purification, and put upon wire of military and other cables which are likely to be exposed to comparatively high temperatures.
The manufacture of electric light apparatus is carried on to a considerable extent at the Charlton Works, .which are lighted by electricity. A steam-engine of 42-horse power is employed to drive the dynamo-electric machines, which are of two classes—one generating continuous currents, which are used for burning powerful single lights; while for burning several lamps in one circuit machines generating alternate currents are employed. In the former machines the electric current is generated in a helix, or coil of copper wire revolving on an axle (in a magnetic field), whence it is taken off by means of a commutator and wire brushes, and conveyed through the electro-magnets (between which the helix revolves), thus treating a powerful magnetic field. From the magnets the current is conveyed by means of ordinary insulated conductors to the lamps. In the latter machine the electromagnets are excited by an independent small dynamo-machine, and the bobbins, which take the place of the helix above mentioned, and are arranged round the axle in the form of a star, revolve in the magnetic field thus produced. The continuous-current machines are made both vertical .and horizontal, and of various sizes, capable of burning lights of from 1000 to about 30,000 candle-power. The lamps used with these machines, of various descriptions, are all manufactured on the premises, and include the focus-keeping and self-regulating lamp with or without silver parabolic reflector; non-focussing lamps with pendulum action; and hanging pendulum lamps, non-focussing and focus-keeping.
Two large shops are set apart for the manufacture of telegraphic instruments, including pointing, recording, and sounding appliances.
Torpedo apparatus, machines adapted to fire off blasts in mines by electricity, insulators, and iron telegraph poles, are among the many other productions of the Charlton Works.
During the luncheon at which the visitors were entertained on their arrival, Dr. Siemens gave an experimental illustration of the mode of effecting the fusion of metals by electricity devised by him some year and a half ago.* In this experiment 5 lbs. of steel scrap were placed in a crucible, through the bottom of which passed an electrode made up of a number of carbons, this electrode being connected to the negative pole of a dynamo machine situated in an adjacent building.
The other pole of the dynamo machine was connected to a second carbon electrode so carried by a balanced beam that it was maintained within the mouth of the crucible. The material in the latter was thus fully exposed to the electric arc, and the fusion of the metal was effected in about twenty minutes.
The Royal Victoria and Albert Docks, to which a party of about a hundred members made an excursion, are the largest of their kind in the world. There are two entrances from the Thames, one at Blackwall Point, and another at Gallion's Reach, below Woolwich. The latter is a new entrance, which saves about 4 miles of river navigation in the Woolwich and Bugsby Reaches. Over the sill of the dock gates the depth of water is 27 ft., and in the dock from 27 to 30 ft. and upwards. The main dock has an area of about 75 acres, and is about one mile and a quarter long, the uniform width between the copings being 490 ft. The aggregate lengths of dock and passage walls, which are constructed entirely of Portland cement made and deposited in situ, is about 3.5 miles. The walls are about 40 ft. high, 5 ft. thick at the top, and from 18 to 19 ft. thick at the base. In addition to the graving docks, there are dry docks in this system, having a length of 510 ft. and 420 ft. respectively along the whole lengths of the north quay; and in the basin there are very extensive sheds, constructed almost entirely of iron; they are 120 ft. wide, the roof being in two spans. The whole of the dock gates, swing bridges, capstans, travelling cranes, &c., are worked by hydraulic machinery. The docks are supplied with injector hydrants, and with a floating crane for the shipment of heavy machinery, the latter consisting of a twin-screw vessel, travelling at five miles an hour, and carrying a steam crane capable of lifting 30 tons to a height of 60 ft. above the water, and of traversing a complete circle of 47 ft. radius. The vessel is 100 ft. long, and 44 ft. broad; the crane is 70 ft, high. The vessel, crane, and counter-balance are worked by steam machinery driven by separate engines, so arranged as to be under the control of one man. Provision is thus made for lifting or transporting any weight up to 30 tons from the quay or from craft into a ship's hold, or vice versa, in much less time than is necessarily occupied by a derrick, for masting or dismasting vessels, and for fitting out or repairing the largest ocean-going steamers. After dark, the docks. are lit up by the electric light (Siemens' system).
The members were courteously received at the docks by Colonel Martindale, the manager, and other officials, and were shown all points of interest. It was intended to visit the Orient steamship, the proprietors of which had made most hospitable arrangements for the occasion, but time unfortunately did not permit.
At these works, which were founded in 1832, members saw carried on all the operations connected with iron shipbuilding, except the manufacture of plates and castings. The angles for the framework are made in the forge—the firm manufacturing their own forgings—and are bent on the bending-floor. The sheds where the ironwork is manipulated are built handy to the slips, and when finished, the work is run across the yard on tramways. Since the introduction of steel into shipbuilding, annealing pits have been added. All the parts that have to be re-furnaced after being received at the works have to be annealed. In the annealing pits they are covered with sawdust or other non-conducting material, which allows of their cooling slowly. The iron plates are chiefly furnished to the works by leading manufacturers in Staffordshire and Yorkshire, steel plates 'being supplied from the works of South Wales and Scotland. They pass into the' large machine-shop, where there are large planes for planing them, the finishing and fitting of armour plates having always been a specialty of the firm. It is the practice of some shipbuilders to get the plates bent and fitted at the different works where they are turned out, but Messrs. Samuda prefer to have them rough and fit themselves. A lever-testing machine in the machine shop is employed to test all materials before being used. There is also a cable-testing machine capable of exercising a strain up to 100 tons. In the smiths' shop a machine of ingenious construction and of the firm's own invention is used for making rivets, Messrs. Samuda Brothers having found it impossible to obtain from any manufacturers a rivet-making machine which would do the work required entirely to their satisfaction. Connected with this machine is a furnace for heating the iron rods from which the rivets are made, five rods being heated at a time. The rods when red-hot go through a cutter which cuts them into suitable lengths. The workman in charge of the machine places a lengths in a mould, and the head of the rivet is stamped by a die which descends upon it. A jet of water constantly streaming over the dies serves to keep them cool. There are two machines for bending heavy armour plates. The larger is capable of exerting a force equal to about 4000 tons, and is used for bending the heaviest turret plates; the smaller has a force equal to about 1000 tons. There is also a hydraulic bending machine, used for bending keel plates, which has four rams capable of exerting a force of about 300 tons. The ironwork department is also supplied with an angle-cutting machine. A revolving furnace is used for making iron joints in heavy iron beams. Formerly the beams used to be carried all round the shop in order to secure the angle at which they were to be welded. By this revolving furnace the necessity of doing so is obviated. In the sawmills a horizontal log-cutting band-saw, which can be raised or depressed by means of a hand-wheel lever placed on either side, is employed. All the cabin-fittings and other joiner-work of a ship are prepared in the joinery department while the hull of the vessel is in course of erection, so that on being launched the whole of her woodwork and fittings can be fixed in their places in the shortest possible time. The shop is fitted with steam-saws, mortising machines, and other labour-saving machinery. The cabin-doors for the ships now under construction are provided with gratings which can be closed by a sliding shutter. There is also a brass-finishing shop, and a separate department is connected with the works, wherein are constructed all the masts, blocks, rigging, and sails used in ships made by the firm; the raw material of the rigging being prepared in the yarn-shop.
The visitors saw, among other work in progress, an ironclad for the Brazilian Government. She is to be armed with Sir William Armstrong's 25-ton guns, to be built of steel, and to be armour-clad, having steel-faced armour plates, 11 inches thick, with a thick backing of teak. Three composite gunboats and a despatch-boat were being built for the Admiralty. The composite vessels are to be built in watertight compartments, the skin being composed of two thicknesses of teak. In the ironclads constructed by Messrs. Samuda Brothers the steering gear is placed at a considerable distance below the water-line, the wheel being kept in an iron pilot tower, furnished with special defensive armour. Connecting rods communicate with a steam-steering apparatus in the lower part of the ship.
On Wednesday, October 12th, nearly four hundred members made an excursion to Woolwich Arsenal, whither they were conveyed in a free special train provided by the directors of the South-Eastern Railway Company. At the Royal Gun Factories the party was received by Colonel Maitland, the superintendent, and other officials, and every opportunity was afforded of seeing all that could be seen within the brief time available for the visit. The general character of the Arsenal and of the operations therein carried on are sufficiently indicated in the papers of Colonel Maitland, Mr. H. J. Butter, and Mr. Davidson on the manufacture of ordnance, gun-carriages, and projectiles respectively. It is therefore only necessary to add here that the following operations were witnessed by the visitors, as per the official programme prepared for and circulated on the occasion:—
Field-Gun Section.— Fitting breech arrangement to 6-inch guns; fitting breech arrangement to 32-pounder S. B.; rifling 25-pounder; screwing and chambering 25-pounder; slotting ways out of breech, 6inch guns; obturators, 6-inch and 32-pounders; turret work.
Light Boring Mill.— Rifling 12.5.-inch 38-ton M. L. gun; screwing breech-end of 6-inch B. L. gun; boring breech-end of 10.4-inch 26-ton B. L. gun; chambering 6-inch 80-cwt. B. L. gun; rifling 6-inch 80cwt. B. L. gun; boring steel block for 6-inch B. L. gun; screwing breech-end of 9.2 inch B. L. gun; boring out tube of 12-inch M. L. gun for repair.
Heavy Boring Mill.— Chambering 12.5-inch 38-ton M. L. gun; boring breech 12-inch 43-ton B. L. gun; tempering steel tube, 6-inch B. L. gun.
Turneries.— Turning breech: coil of 6-inch B. L. gun; turning chase of 6-inch B. L. gun; turning steel tube after tempering, 6-inch B. L. gun; turning trunnion, 6-inch B. L. gun; testing tube by water pressure; turning D. coil for 43-ton B. L. gun; turning for B. tube on 16-inch 80-ton M. L. gun; slotting trunnion for 11-inch 25-ton M. L. gun; turning steel block for 12-inch 43-ton B. L. gun; and turning trunnions for 16-inch 80-ton M. L. gun.
Forges.— Coiling a 9-inch bar for part of breech-piece, 43-ton B. L. gun—length of bar 85 ft. and weighting 85 cwt.; rolling a 6-inch bar for part of jacket for 6-inch B. L. gun; welding the muzzle end of D. coil 43-ton B. L. gun, by 40-ton hammer, weight of coil, 11 tons 14 cwt.; shrinking jacket on to 6-inch B. L. gun; welding a steel coil for 1 B. coil 43-ton gun, by 10-ton hammer; and casting a 3-ton ingot in the new steel furnace.
Various steel forgings, cold bends, and testing specimens cut from the raw ingot without either having been hammered or rolled, were also shown.
Among general objects of interest shown were the 100-ton guns, 80-ton guns, 43-ton B. L. guns, 6-ton B. L. guns, field B. L. guns, a large revolving crane, the Thunderer burst gun, 38-tons, and the 2712. derer gun burst at Woolwich to verify the conclusions of the Ordnance Committee.
Although upwards of two hours were spent at the Arsenal, that time was insufficient to allow of the carriage department or the laboratories and offices being inspected, and it therefore became necessary to forego a visit to these interesting adjuncts of the great national workshop. The members returned to town by the same special train that had conveyed them to the Arsenal.
The annual dinner of the Institute took place in the evening at Willis's Rooms, St. James's, undir the
On the afternoon of Thursday, October 12, an excursion was made by special train to the Royal Small Arms Factory at Enfield Lock, and to the locomotive and carriage works of the Great Eastern Railway Company at Stratford. The following interesting notes on the manufactures of small arms at the Enfield Factory were drawn up by Major H'Clintock, the assistant superintendent, for the use of members taking part in this excursion, and were circulated during the meeting.
THE following arms, &c., are manufactured at the Royal Small Arms Factory:
As it would render these Notes too long if an attempt were made to describe the manufacture of each of the above, a short description only will be given of the process of manufacturing the Martini-Henry rifle and the triangular bayonet.
DESCRIPTION OF THE MARTINI-HENRY RIFLE
The rifle consists of a barrel screwed into a shoe or body, a butt, and a fore-end. The body contains the breech action, which is the mechanism for closing the breech, firing the cartridge, and extracting the empty cartridge case.
The breech is closed by a block which swings on a pin passing through the upper rear end of the shoe or body, the recoil being taken by the shoe. The cartridge is exploded by a direct-acting piston (the striker), which is driven by the action of a strong spiral spring within the breech block. A lever in rear of the trigger guard acts on the breech block, so that the action of pushing the lever forward causes the block to fall, the tumbler to be carried round until the trigger-nose drops into the tumbler bent—the main spring being compressed by this motion as the crane of the tumbler draws back the striker round which the spiral spring is coiled—and the empty cartridge case to be thrown out to the rear. On drawing back the lever, the block is raised so as to close the breech, and the arm is ready to be fired.
The stock is made from Italian walnut, and is in two parts, the butt and the fore-end. The butt is secured in the socket of the shoe or body by means of a screw bolt; and a loop and pin, and two bands, connect the fore-end to the barrel. In the latest pattern rifle the loop and pin have been replaced by a fore-end hook, which engages into a recess in the front of the body.
The stock, which consists of two parts, the butt and fore-end, is made of Italian walnut; this wood, owing to its lightness, hardness, and closeness of grain, being found well suited for the purpose. The rough butts and fore-ends are obtained by contract, and on arrival in the Factory are examined, when, should any of the following defects be observed, they are rejected:
The first ten defects are readily detected by the examining viewers, and should the appearance of the wood lead them to suppose that it has been damaged by salt water, a shaving is taken off with a spokeshave, and is dipped in a solution of nitrate of silver (1 grain to 1 oz. distilled water), when, should any salt be present in the wood, a white precipitate is formed (chloride of silver). Should wood which has been damaged by salt water be used for a stock, it will rust any steel or iron with which it comes in contact, and no method is known by which to remove the salt from wood which has once been damaged.
The butts and fore-ends are usually in a half-seasoned condition when received from the contractor, and are stacked to season in the stock stores.
Green wood requires about three years to season. If it is necessary to hasten the seasoning of the wood, the rough butts and fore-ends are placed in the desiccating room, and subjected to a heat of 60°, gradually increasing to 90° or 100° Fahrenheit. If half dry when placed in the desiccating room, they will be ready for use in about six or seven weeks.
Principal Processes in Manufacture.
The principal machine operations are as follows
The barrel is made of soft or mild steel prepared by the "Siemens-Martin" process, this metal having been found to be of a very uniform nature. The barrel bars or moulds are obtained by contract in lengths of 15 inches, the diameter for rifle bars being 1 inch.
Forging.— The barrel bar is heated to a white heat and passed through the barrel rolling-mill, which consists of ten pairs of rolls arranged alternately horizontally and vertically, when it is drawn out in one heat to the full length required (about 36 inches), taper in form, and solid. It is next passed to the Ryder forging machine, where the " Knox form"' is forged on the breech end and the barrel Cut to length, then passed through a straightening machine, examined for straightness, and viewed as finished forged.
Machine Operations.— The ends of the barrel are clamp-milled for size and length, and then drilled up about 1.5 inch at each end, the diameter of the holes drilled being 0.430 inch. This operation is called "entering the bore," and is very carefully tested to see that the starting of the bore is true and correct. The barrels are now ready for drilling.
Drilling.— The barrels, while being drilled, are placed vertically in a machine, where they revolve with a speed of about 300 revolutions per. minute, the holes already made at each end acting as guides for the set of three drills used in this operation. The method of using these drills ensures a long hole of small diameter being drilled perfectly true, and until this method was adopted this was found to be a most difficult task. The drills consist of, first, "the core drill," for roughly cutting away the metal. This is run in half an inch, when the barrel is taken out and emptied of swarf or cuttings by placing A over a jet pipe, when a strong stream of washing liquor thoroughly clears out the bore. Another half inch is drilled in the same manner, and the bore again washed, out. The second drill, or half-round bit, is now used. This drill is 0.430 inch in diameter, and having only a cut of 0.05 inch to make in clearing the hole, is run down the one inch the core drill has cleared without any risk of deviating from the truth.
The barrel is now again washed out, and No. 3 drill made use of. This has a stock fitting the hole already bored, and ending in a small 3/16-inch drill, which, being supported by the stock, drills away the centre perfectly true with the axis of rotation, ready for the "core" or "roughing drill" to start again. If this system is rigidly carried out inch by inch,. it is possible to drill a hole three or four feet deep with an error of less than 0.005 inch. A set of drills consists of these three just described, and three sets of different lengths are used. When one half of the barrel has been drilled, it is turned end for end, and the operation repeated until the holes meet in the centre.
This system of drilling originated at the Royal Small Arms Factory, and is not in. use elsewhere.
After drilling, the hole is broached out with long square bits, on one side of which a strip of oak is placed. Long strips of writing paper are evenly placed between the strip and bit, one upon another, and the bit is run through the barrel until the hole is broached out to the required diameter. This operation is more of a burnishing character than a cutting one, producing a fine, clear, polished surface, down which a shade is readily thrown by holding the barrel at the proper angle to the light. As shadows thrown off straight surfaces are projected in straight lines on any true surface on which they are thrown, the eye can be taught by practice to detect any inaccuracy in the bore of a barrel by the appearance of the edges of the shadow thrown down it. In order to ensure absolute certainty that no barrel should be passed on for the exterior to be turned, which had not the bore perfectly true, the following mechanical test has been devised, vim:—A steel rod is stretched taut between two horizontally fixed head-stocks, having a collar in the centre and at one end, which fit the bore loosely, so that the barrel can freely revolve on the rod. If the bore is straight, the end of the barrel where there is no collar on the rod will run perfectly true; but if not straight, it will revolve eccentrically, and its motion is easily detected by any unskilled person. Every barrel is passed through this test before the exterior is commenced upon. The bore is also tested for size by the collars on the rod.
The next operation is to support, and hold the bore true, while the outside is turned perfectly concentric with it. After a number of experiments to find out a means of fixing a true turned bush or collar on a rough exterior, the present method of running sulphur in a liquid state between the barrel and bush was adopted. By this means the exterior of barrel can be turned perfectly true with the bore, without injury to the inside. The barrel is placed vertically, when two plugs, whose centres coincide with the axis of the barrel, are placed in the breech and muzzle; the bush is then held over it and melted sulphur is poured in between barrel and bush. This gives a bearing for the outside perfectly true with the bore.
Turning.— The barrel is now rough-turned, finished-turned, draw-polished, gauged, chambered for proof, and screw-thread cut in breech end, to take the "butts" used to close the breech during first proof.
This system of turning a barrel enables its exterior to be brought to a definite size, and is greatly superior to the old method of grinding barrels on a large stone, and afterwards striking them up.
First Proof.— The barrels now undergo the first-proof test, which is necessary in order to detect inferior quality of metal, and flaws which do not appear on either the exterior or interior surfaces. The first proof charge is 71drams of powder, a lead plug of 715 grains, and over the latter a cork wad half an inch in thickness. Twenty barrels are proved at the same time in a cast-iron proof battery.
Finished Milled.— The seat for the front sight is now cross-milled and dovetailed, and the steel for the front sight is sawn to length and brazed on. The barrel is now finished-bored and set, and is then ready for rifling.
Rifling.— The rifling is done with a cutter having a head of suitable form for the rifling required. This is fitted into a groove cut in a box about eight inches in length, and fitting the bore. It is drawn through the barrel by a rod fastened to one end of the cutter box, the other end of the rod being coupled into the spindle of the head-stock or traversing saddle. On the spindle is a pinion geared into a sliding rack carried by the same saddle. The end of the rack is fitted to slide backwards and forwards along a fixed bar, which can be set at any angle necessary to rotate the spindle and cutter box to the amount of spiral required. From four to five cuts are needed for each groove, and the cutter is fed up by a screw tapped into the end of the cutter box, to which a rod is attached, which works through the centre boss of a hand wheel. A spiral groove is cut along this rod, in which a feather fixed in the boss of the hand wheel slides, enabling the feed-screw to be screwed in or out by the hand wheel as required. An index is connected with the hand wheel, enabling the operator to read off the depth of cut. The barrel is fixed in a rotating chuck, which is divided so that any number of grooves required can be cut inside the bore. The rifling is of a uniform twist of 1 in 22 inches, or one and a half turns in the length of bore (33 inches). The form of rifling is that known as the "Henry rifling;" the grooves are seven in number, and are 0.007 inch in depth.
Screwing and Chambering.— The barrel is suspended inside a hollow rotating spindle by a plug inside the muzzle end, running on a plug fixed in headstock at the breech end. A guide-screw is securely fixed on the rotating spindle, and carries a nut fixed to traversing tool-holder, which holds a peculiar form of chasing tool. The teeth for cutting the screw-thread on the breech end are on the underside, so that, being set over the top of the rotating barrel, it can be lifted in and out of the thread which is being cut, in the shortest possible time and distance, without chopping the thread.
The screw being finished, the barrel is driven from it, while the breech end is chambered up for the cartridge. This is an ordinary operation of boring and reamering in a lathe.
Second Proof— The barrel is now breeched up to body, the action assembled for proof, and the rifle undergoes the second-proof test. The second-proof charge consists of 5 drams of powder, a bullet weighing 715 grains, and a cork made half an inch in thickness. The barrels are proved in a proof battery something similar to that used for the first proof.
Sighting.— The back sight-bed is soldered on to the barrel, and also secured in its place by two screws. Both the back sight and front sight are adjusted and regulated from the axis of the bore, and when viewing the barrels for sighting, the greatest care is taken to see that both sights are exactly in position.
Browning.— The body and barrel are browned separately, the following being the browning mixture at present in use:—
The process is as follows: —The barrels and bodies are first scalded in a solution of soda for twenty minutes, and are then washed in clean water. The browning mixture is applied, and they are placed in a damp heat for about one and a half hour, when they are scalded again, and when cool, the rust is scratched off.
This process is repeated four times, and then the barrels are cleaned off and oiled. The whole operation of browning takes about eight hours.
Material.— The body is made from a specially tough class of mild steel. Bars of this metal, 4 or 5 feet in length, and 2 inches by 1.5-inch in section, are obtained by contract.
Forging.— The body is blocked direct off the end of the bar by five blows under a 15-cwt. steam-hammer.
The first blow gives a rough figure, and measures off the quantity of metal required.
The second blow fullers in the sides of the body, to displace the metal when working the hole through it.
The third blow, by means of a chisel in the upper die, splits the metal in the centre, driving out the sides of the body to fill the die, and leaving the impression of the hole, to be made through the body, full size at top.
The fourth blow drives a full-sized drift, placed in the hole just made by the chisel, clean through; shearing down the sides, and driving through the small piece left at the bottom of the hole. The hole made through the body is now 3 inches by inch by 21 inches, and the metal wasted is only 3i oz. in weight.
The fifth blow cuts the body off the bar. A mandril is now driven in the hole, and a blow is struck upon the ends to square them up, when the body is ready for stamping.
Stamping.— The body is reheated and a cold steel mandril driven into it, when it is at once placed under a powerful steam-hammer. On the anvil of this hammer is the lower die of a pair, the impression cut in the pair of dies being that of the finished size of forged body. One heavy and sudden blow is given, with force sufficient to make the metal flow into every corner of the impression. If this is not done at the first blow, it cannot with safety be attempted by a second blow without reheating, as the surplus metal flows over between the faces of the dies in the form of a thin fin, chilled and black, and this would swallow up itself the force of a second blow, and perhaps split one of the dies.
The body is next annealed, scale pickled off, fin trimmed, and passed as "finished forged."
Machine Operations.— The hole in the body is first drifted out by means of long, slightly tapered drifts, which are drawn through it, and the hole thus produced is used as a starting-point for all the subsequent operations. After drifting, four bodies are placed on a revolving cross-shaped fixing, the arms of which exactly fit the holes in the bodies, while a transverse slide carrying two tool-holders, one on each side, turns up both sides of the four bodies at one operation. This operation leaves the sides of the body equal in thickness, and true with the centre hole.
Twelve bodies are next fixed on a revolving head, and the barrel ends are all cut square and true, the stock ends being treated in the same manner.
The hole for the barrel is then drilled, tapped, and the burr thrown up by tapping is smoothed down. The face is eased, so that when a gauge is screwed in, it stands exactly true. The body is now placed in a drilling jeg, and the adjusted face is screwed tight up against a rib in the jeg, while the six axis holes of various sizes are drilled, three in each side. The drills run through hardened steel bushes fixed in the sides of the drilling jeg.
These axis holes, after being tested for accuracy, become, in conjunction with the large hole in the body, the base points for the remaining operations.
A number of drilling machines now operate to cut away the metal, so as to form the socket to receive the stock butt. The hole is drilled and tapped to receive the screw end of the stock bolt, which secures the butt in the socket. Pins in the axis holes in the left side of the body, hold it while the knuckle seat for breech block is roughly cut out, and the seat milled out square and true. A number of minor milling, drilling, and tapping operations bring the body into the shape and figure required, and it is then screwed on, or "breeched up," to the barrel. The barrel is now placed vertically with the end of the chamber resting on the collar of a plug, which enters and exactly fits the chamber, and the face of the barrel is drawn tight down on this collar by means of plugs pushed through axis holes in the body. Small mills are now run on a spindle through the block axis-hole, and finish cutting out the knuckle seat of the block to a positive length from the face of the barrel. This length between the knuckle seat of the block and the face of the barrel is rigidly maintained, so as to ensure that any block will interchange or fit in any body. In order to ensure that this may be the case, each breeched-up barrel and body is accurately gauged with hardened steel gauge blocks. Care is also taken to see that the striker hole, in the face of gauge block, coincides with the axis of the bore of barrel, to ensure the cap of the cartridge being struck in the centre.
The barrel and body are now passed on for assembling the action for second proof.
A particular form of emery wheel, called a "rim wheel," has been introduced for finishing up some of the components. Its use has enabled unskilled labour to take the place of a high class of skilled workmen, and the work is better finished. For instance, the slot of the back sight leaf is first drifted to its true size. By this it is held in a fixing attached to a vertical axis, and both edges with cap attached can be passed across the face of the rim wheels, maintaining it perfectly true, and grinding the edges of the leaf and cap parallel to each other. The sides are done in the same manner.
Having given a short description of the processes of manufacture for the rifle, barrel, and body, it will be unnecessary to describe the manufacture of the other components. The method pursued in the manufacture of all is precisely that followed in the case of the body. All the parts are first of all forged in dies, the fin is trimmed off, they are pickled to remove scale, and then undergo numerous milling, drilling, and other machine operations, until they are brought to the correct figure, when they are viewed, gauged, and either case-hardened, browned, blued, hardened, and tempered, &c., as the case may be.
The barrels of carbines and pistols are treated in the same manner as the rifle barrel. In order to ensure an absolute interchangeability of the various parts, the most exact system of gauging is a necessity, and the strict view which is enforced, prevents the possibility of any defective parts being assembled in an arm.
The following list gives the nomenclature of the remaining parts of the rifle, and the materials of which they are made:—
[Table omitted – see original volume]
THE TRIANGULAR BAYONET.
The blade is made of tool or sharp steel, the socket of mild steel, the locking ring of wrought iron, and the locking ring screw of steel.
The blade and socket are welded together; the blade is tapered under a Ryder hammer, and then rolled out in segmental rolls to the required length and a triangular figure.
The socket is stamped to size, and then goes through several machine operations, such as drilling, milling, slotting, &c.
The blade is hardened and tempered, ground and polished; the socket being browned. The locking ring is blued, and its screw is casehardened.
HARDENING AND TEMPERING COMPONENTS.
The breech block, lever, butt plate, and iron screws, are casehardened. This is done by carefully packing them in iron boxes, in which they are surrounded with bone cuttings or animal charcoal. An iron plate is laid on the top of the box, and it is placed in a furnace and raised to a red heat. The length of time that the various articles are left in the furnace, depends on the amount of case-hardening required; and when removed from the furnace they are chilled in a tank of cold water. They are then cleaned, oiled, and examined by gauges to ascertain whether the case-hardening has altered their form.
The following components are hardened by being raised to a certain temperature and then cooled in oil. They are afterwards tempered by "blazing," that is, by heating them again until the oil or suet with which they have been covered, bursts into a flame:—
Striker, main spring, indicator, extractor, sight spring, catch-block spring, trigger spring, block axis pin, extractor axis, sight slide, and steel screws, &c.
The following components are blued:— Upper and lower bands, upper and lower band pins, guard and band swivels, fore-end hook screws, sight leaf, lever catch-block and pin, guard, nose-cap, rod-holder, &c.
They are polished, cleaned with lime to remove grease, and are then covered with powdered charcoal and raised to a temperature of about 550° Fahrenheit.
ENFIELD BREECH-LOADING REVOLVER.
This revolver differs from the patterns usually met with in having a rebounding lock, and in its method of extracting the empty cartridge-cases.
The principal parts are the barrel, the cylinder, and the body.
The barrel is 5i inches in length, and the diameter of bore and the form and twist of the rifling are the same as in the rifle. The barrel is attached to the body by means of a screw passing through a knuckle-joint in an arm which projects below the breeds end. It is held in the firing position by a spring catch in front of the hammer. The "axis pin" of the cylinder is screwed into the body, its point resting in a recess in the joint-arm of the barrel. A projection or boss on the cylinder engages in the same recess. By this arrangement, when the catch holding the top bar is released and the barrel depressed, the cylinder is drawn along its axis, and the bases of the cartridges in the chambers being held by a radial extractor, which is free to move only a short distance along the " axis-pin," the cartridge cases are drawn from the chambers to such a distance that those which are empty are free to fall away, while filled cartridges are held by the bullets remaining in the chambers. The cylinder contains six chambers, and the pistol is loaded in the ordinary way.
The lock action consists of seven components, viz.:— hammer, axis screw, trigger, trigger axis screw, pawl, lever, and mainspring.
The mainspring governs the movement of each component. The act of pulling the trigger cocks the pistol and fires it, and upon the release of the trigger the hammer rebounds to half cock.
The stock is of walnut, and the remaining parts are of steel.
The system of manufacture is similar to that of the rifle.
Weight of pistol, 2 lbs. 8.5 oz.
The carbines of the cavalry and artillery patterns have the same calibre as the Martini-Henry rifle (0.45 inch), and have also the same twist and form of rifling, but the barrels are only 19 inches in length. The processes of manufacturing the various parts are precisely the same as those for the rifle.
With the assistance of Mr T. Perry, Manager R.S.A.F., these notes have been compiled for the use of the members of the Iron and Steel Institute, on the occasion of their visit to the Royal Small Arms Factory.
W. M'CLINTOCK, Capt. R.A., Asst. Supt. R.S.A.F. 28th Sept. 1881.
The locomotive and carriage workshops at Stratford, which were visited by a section of the members, employ over 2000 hands, and are occupied mainly with the repair of the 600 locomotives, 2000 carriages, and 10,000 waggons which form the rolling stock of the Great Eastern Railway. The works are fitted with all the various machines usually required in the repair and renewal of rolling stock, and are divided into locomotive construction, locomotive running sheds, carriage-building, and goods' waggon departments. The fitting and erecting shop is a structure about 348 feet long by 142 feet broad, the central portion of which is occupied for erecting purposes, while a number of fitting and other shops are ranged around. Here are a number of small self-acting wheel-lathes, a large slotting machine and drilling machine, a millwrights' bench and motion bench; a brasswork shop, where the connecting and coupling rod, brasses, eccentric sheaves, injector, gauge, and other cocks and fittings, safety valves, and clack-boxes are adjusted; a brake-shop, devoted entirely to the gear and fittings connected with the Westinghouse brake; an axle-turning lathe and fitting bench, where also pistons are turned and fitted with heads. Here are also ten large planing machines, which do all the general work of the shop—the planing of axle-boxes, horn-blocks, and coupling and connecting rods; a bench where bogies and frames are fitted up. Cylinders are brought here in the rough, planed and fitted up ready for the engines.
Tramways run to every part of the works, upon which the various materials are brought hither. The centre of the erecting-shop is occupied by the frames of the engine. The boilers, having been fitted with tubes and expansion brackets, are here tested with warm water to a pressure of 200 lbs. to the square inch. They are then conveyed by a crane to the frames and gently lowered into position; cylinders, taps, cocks, exhaust pipes, pistons, connecting rods, &c., being then adjusted. Close at hand is the small machine-shop, where many of the smaller fittings are turned and slotted, drilled and finished—weigh-bar shafts, eccentric straps and sheaves, valve spindles and guides, motion blocks, connecting rods, wrought-iron bogie pins, reversing screws, &c. Here there is a milling machine for cutting cutters, taps, stops, and dies. Part of the shop is given over to brasswork—injectors, whistles, steam-cocks, mud-plugs, slide-valves, and so forth, being brought in rough from the brass-foundry and machined. The patternmakers' shop also occupies a corner of this building.
The wearing parts are all case-hardened by being put into an iron box or tank with a mixture which includes charcoal, bones, and leather. The casket is sealed with fire-clay and slowly heated in a furnace till red hot, when it is drawn out and sunk into a well. There is a large iron-foundry with three lofty cupolas, core-ovens, several moulding machines, cast-iron patterns being much used, and a 5-ton travelling crane, lifting, traversing, and travelling by power, the motion being controlled from below. All the usual castings for a railway are made here, one of the cupolas being reserved for locomotive cylinders, horn-blocks, &c. In the brass-foundry (in which Fletcher's furnace and plumbago crucibles are used) and coppersmiths' shop the copper tubes for steam-pipes are made, iron boiler tubes are brazed with copper to the length of nine inches at the fire-box end, and are tested to a certain pressure.
In the boiler-shop the plates are cut to the size required in a shearing machine and afterwards punched. They are then bent between rollers and riveted by a patent hydraulic riveter on Tweddell’s system. The copper fire-boxes and fire-box casings are also made and riveted here. In another part of the boiler-shop various kinds of lighter work are turned out, such as ash-pans, smoke-boxes, the splashers of driving-wheels, coalbunkers, and tanks. The shop contains drilling machines and boring machines for drilling the tube plates and boring the holes for the centre domes of engines, the latter being done before the plates are bent. There is also a large machine by Hulse of Manchester for facing up the edges of the boiler-plates before they are riveted or bent, while lifting power is furnished by two 10-ton cranes, two 5-tou cranes, and two or three hand cranes.
The running-sheds, two in number, are capable of holding 25 and 30 engines respectively. The carriage department is -well fitted, but neither this nor that devoted to the repair and renewal of waggons calls for notice here.
It had been proposed that, after inspecting the new quay and the site of the new dock, members should cross the harbour in barges for the purpose of inspecting the breakwater, the west pier, and the seawall, but the very high wind which prevailed made it impossible to carry out the latter arrangement. It was, however, possible to obtain a general idea of the extensive character of the improvements in course of being carried out by the Railway Company, and comprising, according to an official statement drawn up by Mr. Banister:
1st. A breakwater, about 1000 yards in length, to be run out seaward from the shore at Barrow Head, westward of the harbour, in a direction to protect the entrance of the harbour from the prevalent south-western and southern gales. More than 300 yards of this breakwater are now completed.
2d. The extension of the two entrance piers, and the widening of the entrance from 150 to 200 feet.
3d. The construction. of a new wharf or quay between the Mill Creek and the eastern entrance pier, thus affording additional quay space — about 600 yards in length. It is intended to widen the harbour opposite this new quay, and deepen it to 12 feet at low-water spring tides.
4th. The construction of a dock, with entrance lock and gates, on the marsh land between the harbour and Catt's Tide Mill, with a water area of 24 acres, and quays of about a mile in length.
5th. The construction of durable sea-walls to protect the foreshore and works, extending from the breakwater on the west to Catt's Mill on the east.
6th. Dredging the whole of the existing harbour to a uniform depth of 6 feet at low-water spring tides, and the entrance and new portion up to the Mill Creek to a depth of 12 feet; as well as the dredging of the space outside protected by the breakwater to a depth varying from 12 to 18 feet at low-water spring tides.
In connection with these improvements, all the necessary wharves, landing stages, tramways, cranes, sheds, and other appliances for carrying on a large trade, are being provided.
The breakwater at Newhaven is being constructed entirely of concrete, and sea-walls of the same material are being constructed to protect the foreshores, to lengthen the entrance piers of the harbour, and to widen the entrance.
From Newhaven the party were conveyed by their special train to Brighton. Here an excellent luncheon was provided for them by the Local Reception Committee in the Dome of the Pavilion. Sir Henry Bessemer, as Chairman of the Committee, presided. After luncheon, the locomotive works of the Brighton Railway Co. were visited, Mr. Stroudley, the locomotive superintendent of the Company, and other officials, receiving the visitors and showing them over the different departments.
At the Brighton Works, the greater part of the rolling stock used by the Company is turned out, and, up to the present time, more than 220 new engines have been constructed. The erecting-shop is 82 feet wide by 380 feet long, having four lines of rails and a row of columns up the centre, with a roof in two bays. This shop is fitted with four hydraulic travelling cranes, designed by Mr. Stroudley, and made by Messrs. Tannett, Walker, a, Co. of Leeds, from his drawings.
The lifting cylinder has a spherical collar placed at about the middle of its length—the cylinder itself being 11 inches diameter—and has a piston fitted with ordinary hemp-packing. A rod passes down from the bottom of the cylinder, having a gland similarly packed, and with a swivel spring at the bottom. Suitable hooks are made to take hold of the buffer beam, and a proper pair made to fit into the drag bolthole in the after buffer beam, and by attaching the cranes to these the engines are lifted without damage or trouble. The carriage on which the hydraulic cylinder is slung is fitted with a set of three-throw plunger pumps, which are always at work while the crane is in action. The water is allowed to escape by a bye-pass back into the tank when it is not required, and a separate handle with a stop-valve is provided for lowering when necessary. Thus the hoisting is done by the direct action of the pump, which forces the water through a stop-valve on the side of the cylinder, the connection between the pumps and the cylinder being made by a spiral pipe of sufficient elasticity to allow the cylinder to move about as may be required, and the discharge water passes through an india-rubber hose back into the tank. The shafting, running down each side of the centre column of the erecting shop, is driven by a tight and slack pulley, geared at the end of the shop. The belt can be moved into and out of gear by a rope passing over the head of the crane-man.
The carriage-shop is 900 feet long and 25 feet high, its entire area extending to nearly seven acres. Steam pipes, 7 inches in diameter, are used to heat the building. On one side of the carriage-shop, carriages are fitted with the Westinghouse air brake, which has now been applied to about 1600 of the Company's vehicles.
The Company make their own boilers. The plates, after being planed at the edges and heated slightly, are bent to the desired form and drilled, the longitudinal joints being placed above the water-line, and fitted with butt-strips inside and out, each double-riveted. The rivets are countersunk through the butt-strip inside and out. These rivets are driven home by hammers of about 7 lbs. weight, and having to be forced into the countersink only, are very quickly closed. The manhole ring is made of wrought iron, with a very thick flange. The metal used is a piece of angle bar, 14 inches by 1 inch, and 4i inches by 2 inches; this is bent round, welded, and flanged to fit on to the boiler, the butt-strip for the joint in the boiler-plate being welded thereto, the upper face for the dome being turned; and after riveting 0., it is scraped up to a steam-tight joint, so that the dome can be easily taken off and put on. The inside butt-strip is prolonged to hold the regulator. Tubes 12 inch diameter outside are used, and the thinnest end of the tube is placed next the fire-box. The tubes are spaced i-inch apart, and in one class of engine they are 262 in number. The fire-boxes are of copper, the tube plates being 1 inch thick. All rivets are of iron. The forward end of the internal fire-box is made with nearly square corners and a flat top to admit the greatest possible number of tubes, but further back the roof is curved. The stays, therefore, have to be somewhat differently arranged in the two places. The tendency of the stays being to pull down the crown of the shell and stretch it at the sides, two heavy cross stays with large palms at the ends are riveted on. The front tube plate is of steel, this being the only steel plate about the boiler. It is secured to the shell by two angle-iron rings, with a view to prevent grooving.
The engines made for goods traffic at the Brighton Works have 17-inch by 26-inch cylinders and 5-feet wheels, and those for passenger traffic have cylinders 17 inches by 24 inches, with wheels varying according to the nature of the trains to be worked. For the suburban lines and branch work, a light engine, now known as the " Terrier," in which the whole of the weight of the engine is utilised by coupling all six wheels, was designed and is largely used. This engine has, as nearly as possible, one-half the proportions of the full-power engines. Examples of each of these types of engines were exhibited in front of the Company's carriage-shops.