CHAPTER III.
WORKING IN METALS.
It would be of great advantage to every traveller if before starting on an expedition he were to spend a few hours in learning from a blacksmith how to weld together two pieces of iron, and from a tinman how to solder tin or copper. In the absence of this experience, a man who is determined to help himself need not despair of success if he will bear in mind that the chief essentials in both cases are proper heat, strict cleanliness, and sufficient quickness of manipulation without hurry. If the traveller possesses a portable forge, it is most likely he will have learned how to use it before starting; if not, he may in many countries, South Africa especially, find almost in every tribe some native who could make one; or if not, he might adopt some of the expedients described under that head. His first care should be to see that his fire burns clearly and with sufficient intensity, and this he may aid by occasionally dashing in a little water, which, by the decomposition of the gases, will increase the heat under the direct blast, while the surplus, falling on the surrounding coal, will prevent the fire spreading farther than is requisite. The broken ends of the iron to be rejoined should then be placed in the fire, one of them in the centre of the heat, and the other near enough to acquire a preparatory warmth; the first, heated to a bright orange red, should be taken out and thickened by stamping the broken point upon the anvil till it is considerably shorter than before; if the heat is sufficient, the scarf, or smooth diagonal surface which is to form one part of the welded joint, may be worked upon it; if not, it must be returned to the fire while the other part is taken out and driven up in the same manner. In using the hammer, some care is needful to proportion the force of the blow to the size and comparative heat of the metal you are working, and also to turn the iron under the hammer so that each stroke shall help to consolidate the mass instead of splitting it into fibres. When the surfaces of the scarf are worked smooth, fair, and perfectly free from scales or dirt of any kind, place them side by side in the fire and bring them to an intense white heat, so that when drawn forth they may almost spontaneously give off small white sparks. We would add a caution against burning the iron, or partially fusing it, by too much heat, but we do not think a traveller with an extempore forge is in much danger of doing this. The anvil should now be perfectly clean; the “smith,” with his hammer ready in his right hand, should grasp with his left one of the pieces while his attendant draws out the other and lays it with the scarfed side uppermost on the anvil; prompt action without hurry is now the one thing needful: the smith withdraws his piece, lays it with its scarf turned downwards on that of the assistant’s, and with one decisive stroke of the hand-hammer unites them; a few more smart and rapid strokes while the iron is slightly turned to and fro to receive them properly, complete the union; and when the first heat is lost the iron is again put into the fire, and the joint which, owing to the thickening and shortening previously described, should present a clumsy appearance, may be trimmed and hammered down to its proper dimensions, the iron, if this is neatly done, having lost but little of its original length; and it is now for the operator to judge whether he will restore this by beating the metal a little thinner or sacrifice a little of it for the sake of retaining the original thickness. Among the Kafirs a rock is most frequently used for an anvil, and a smaller stone for a hammer. The West Africans use a conical block of iron, about the size and shape of the link extinguishers, some of which may yet be seen before old houses in London. The work has, in consequence, a slightly indented appearance, which distinguishes it from the smooth-faced hammer-work of England; but their weapons are of excellent metal, and so flexible, that they will almost tie in a knot rather than break. The Abyssinians also use weapons of this temper; for they say if a steel sword breaks, who can mend it, but if it bends we can sit on it and straighten it.
Scrap and hoop iron.
We have often made very good knives for skinning or cutting up animals from the handles of broken gridirons, frying-pans, stout hoop, or other bits of iron. Broken sheep-shears are also excellent substitutes. The hoop iron used to bind the bundles of compressed hay issued to troop horses can be made use of for an immense number of useful purposes. The walls of many of the stables we erected in the Crimea were composed entirely of this material, closely interwoven, like basketwork. Excellent gabions can be made from it, as can the framework of hut roofs. A piece a couple of yards long, doubled forward and back in zigzag form, makes an excellent gridiron. Short pieces, straightened out by hammering, form useful make-shift knife blades for the use of native servants. Tent poles are greatly strengthened by having a spiral strapping of this iron nailed to them. Saws for cutting or rather fretting blocks of stone can be made by stretching a strip of this material edgewise in a wooden frame, aided by water, sharp sand, and a suitable balance weight, such as marble masons use. Excellent eel traps are made by arranging long strips of hoop for a body, and then securing them by small nails, as rivets, to hoops made from the same material. Eel traps will be fully described under the head of “[Fishing.]” We once made a complete set of bars for the bottom and front of a camp stove entirely of forage hoop iron, made a scraper for the door, a set of hooks for a gun rack, and a set of cross hooks to hang meat on. Never heedlessly throw away forage iron.
Trimming and filing up are matters which may be left very much to the taste and opportunities of the traveller, but it should be remembered that, cæteris paribus, a neatly finished piece of work, besides being more satisfactory to the eye, is in itself stronger, as the inequalities, flakes, flaws, or roughnesses of the surface, which, under any strain, might form the commencement of a fracture, are removed; and besides this, especially in wet climates, a well smoothed piece of work is less liable to rust in patches than one of unequal surface. If you intend to file-finish your work, remember to let it cool slowly, and do not harden it by immersion in water.
The use of cold or of joiners’ chisels.
In some cases incisions may be required, too sharp or clean to be cut with a file, and, if proper care be taken, a fine, sharp, joiner’s chisel may be used without more injury than may be set right by fresh grinding it; it is advisable, however, first to render the angle at which the edge is set a little more obtuse, so as to lessen the danger of flawing it, taking care at the same time to keep it as keen as possible.
Tires and wheels.
In all expeditions in which wheeled vehicles are used, nothing causes more trouble than the loosening of the tires, owing to the shrinking of the woodwork, and possibly some slight expansion of the metal, from the heavy pressure on the rough roads, as well as from the intense heat of a tropical climate. If sufficient skill be available, the proper course is to cut and shorten the tire, for all other make-shifts have the disadvantage either of being insecure, or positively injurious to the fabric of the wheel. Supposing the shortening to be determined on, the tire must be taken off, and if, as is frequently the case, it be fastened with rivets through the felloes, the clinch on the inner ends of the bolts must be first cut or filed away, the “washers” or iron rings taken off, and the rivets themselves driven back with a long punch or drift pin; the “band” or tire will then either fall off or require but a few blows to detach it. The streaks used to protect the wheels of field artillery guns and waggons are removed and replaced separately.
It is impossible to measure the relative circumference of the felloes and the inner side of the band without an instrument similar to the perambulator; i. e. a wheel or disc of wood or metal, mounted on a handle. A chalk mark is made on the felloe and a corresponding one on the edge of the disc; the two are set together, and the disc—say 1ft. 6in. in circumference—will then revolve perhaps ten and a half times in going round the hinder wheel of a Cape waggon of about 5ft. diameter. As soon as the disc has again reached the starting point another chalk mark is to be made upon it, and the distance between the two marks on the disc, say 9in., is to be added to the number of revolutions counted; it is then to be applied to the inner side of the band, the ten revolutions counted off, the additional 9in. to be run, and the distance between the starting point and the finish of its course is the amount by which the band is too long. Some judgment is required to decide whether more or less than this piece shall be taken out. If the wheel looks very firm and close in its joints, perhaps a little less should be cut, as the overlapping of the weld will take up a trifle—especially if it be not very skilfully and neatly done; if the wheel is loose and the spokes not firmly shouldered up to the nave, a little more may be taken away; and in this case it is proper to estimate whether the felloes will close up sufficiently to force the spokes home upon the nave; if not, the ends of four or more felloes opposite each other should be cut a trifle shorter with a fine tenon saw, great care being taken not to cut the dowels by which the ends of the felloes are kept true to each other. A smooth, hard place must now be sought out, on which the wheel can be laid flat, the front downwards, a hole being dug, if necessary, for the reception of the nave; flat stones, plates of iron, or slabs of hard wood, laid evenly under the circumference, would be of advantage when the shortened band is to be driven on. The next essentials are plenty of water and abundance of heating power. The ends of the band must now be heated, and the smith will bevel off each of them, one from the inside and the other from the out, so as to form the scarf; an attendant or two holding the band, as he directs, upon the anvil. The tire should now be reversed, and the curvature increased by resting it on two points of support and striking heavily between them on its inner surface till the scarfed ends close upon and begin to overlap each other. It is again placed in the fire with the ends equally exposed to the intense heat, and at the proper moment is lifted out by two attendants and promptly, but carefully, placed upon the anvil; a few smart decisive blows are given, and the joint is made. The hammer man now comes to the assistance of the smith and consolidates it by striking alternate blows with the “sledge,” under his direction. The circumference is again tried with the revolving disc, and if it be too short, as it ought rather to be, it is again heated and hammered out, the weld, if this be rightly done, gaining solidity in the process. The band is then laid upon the ground and a fire of wood, dry cow dung, or other material made, so as to heat it to redness through its whole circumference. It is then lifted by tongs or other means (if hooks are used they must be applied from the outside), and placed upon the wheel, and, as quickly as possible, hammered down nearly into its true position. The workmen will soon find what “smoke to the eyes” is like, but they must disregard this, and, before the wood is too much burned away, quantities of cold water must be dashed on, the hammer men all the while beating down the shrinking band to a level with the felloes; before it is quite cold the wheel should be caught up and brought to the anvil, or a smooth rock, where the tire is faced up true to the felloe front by heavy blows, and finally cooled off and tightened by another deluge of cold water.