Robust construction involves weight. Precisely what this means may be gathered from the fact that the German 52-inch lifting-magnet weighed 3 tons, whereas its British rival, to which I am referring, weighs only 2¹⁄₂ tons and has a 20 per cent. greater lifting capacity, despite the reduction in weight of the magnet itself. The magnet in question will lift from 900 to 33,600 pounds—even more—according to the character of the material to be handled, the lower figure applying to sheet-iron, scrap, and bolts, while the other extreme refers to heavy solid steel ingots or armour-plate.
Precisely why the lifting-magnet should have taken so long to establish its virtues, both in this country and the United States of America, is somewhat inscrutable, especially in the latter country which, as a rule, is disposed to introduce time-and labour-saving appliances with alacrity. No matter from what point of view it may be regarded, it represents the biggest time-and labour-saver as well as money-maker yet introduced into the steel industry.
One reason advanced for its comparatively slow adoption is rather interesting. It was averred that to the men, accustomed as they were to seeing loads slung by chains, the sight of a mass of steel clinging to the face of the magnet by a force which they could not understand verged on the uncanny. They knew little or nothing about magnets except in the form of a toy, and could not understand that sufficiently attractive effort could be exerted to keep the mass adhering to the flat face of metal. The fact that the moment the current was switched off released the load was something equally beyond their comprehension. Forthwith they arraigned the lifting-magnet as dangerous, and, while not openly condemning its use, declined to work in its vicinity. Whether this was so or not has never been fathomed, but it is generally observable that men working with such an appliance observe a wise discretion, and refrain from working or moving beneath it. This very respect for the apparatus has achieved one distinctly valuable result: accidents are few and far between, even in America, in which country respect for human safety is declared to be at zero, where the handling of huge masses of metal is conducted by the lifting-magnet.
But, eliminating the psychological effect upon the workmen, it is to be feared that employers were slow to visualize its advantages. Certainly in Britain there are many employers, who, notwithstanding the impressive array of figures advanced in its favour, and who have been brought face to face with the economies it is able to effect, still cling tenaciously to antiquated practices.
So far back as 1911 Mr. H. F. Stratton, in drawing the attention of the American Foundrymen’s Association to the possibilities of the lifting-magnet, presented some illuminating figures. At that time the American steel industry was handling 10,000,000 tons annually by this system and thereby was saving over £200,000—$1,000,000—a year. So far as scrap was concerned he emphasized the opportunity it presented in this field, because, out of an annual melt of 6,000,000 tons of pig-iron and scrap, from 1,000,000 to 2,000,000 was represented by scrap-iron and steel.
The American railways were among the first to appreciate the possibilities of the system. The Chicago, Rock Island and Pacific Railroad introduced the idea for handling scrap and iron in 1909. Up to that time all scrap had been handled by hand, the cost in and out ranging from 30 to 35 cents—15d. to 17¹⁄₂d. per ton—which, according to the authority cited, could be accepted as applicable to all the railways following such a practice, and to record which figure, be it noted, demanded excellent arrangements and efficient organization. Upon the introduction of the lifting-magnet these costs were immediately cut down to 10 to 12 cents—5d. to 6d.—per ton, in and out, inclusive of every expense, the figure for the actual sorting being only 4 to 7 cents—2d. to 3¹⁄₂d.—per ton. The authorities of this railway stated that unsorted scrap could be unloaded by means of the magnet for 2 to 5 cents—1d. to 2¹⁄₂d.—per ton, while, if the scrap were sorted, the cost came out ¹⁄₂ to 1¹⁄₂ cents—¹⁄₄d. to ³⁄₄d.—per ton! Similar work conducted by hand labour, according to the previous practice, cost about three times as much.
That the experience of this one railroad was not isolated was proved by the experience of the Lake Shore and Michigan Southern Railroad, which supplied Mr. Stratton with the following comparative figures for other operations incidental to the conduct of its work:—
| Loading locomotive tyres by hand | 17 cents (8¹⁄₂d.) |
| ” ” ” crane with chains | 8 ” (4d.) |
| ” ” ” ” magnet | 4 ” (2d.) |
| ” heavy casting by crane with chains | 20 ” (10d.) |
| ” ” ” ” magnet | 3 ” (1¹⁄₂d.) |
| ” ” ” hand | almost impossible. |
It will be observed that the handling charges by the magnet were one-half of those by the crane with chains in connection with the locomotive tyres, and one-seventh in the case of the heavy castings, while the advantage over manual effort in the case of the first-named was no less than 32·5 per cent. Little wonder that, during the past nine years, the utilization of the lifting-magnet in connection with the handling of iron and steel in the United States has advanced by huge strides. To-day it constitutes an integral part of the wrecking equipment of every leading American railroad. After the large debris has been cleared up, the lifting-magnet is swept over the ground to pick up nuts, bolts, nails, screws, and any other odds and ends of a ferrous nature which have escaped recovery by the conventional methods.
So far as these islands are concerned, considerable progress has been made during the past five years in regard to its adoption. Extended use has not been confined to the handling of metal in our steel-works, but for the reclamation of iron and steel cargoes which were lost as a result of the German submarine activity. Its employment in the salvage field was suggested as the result of the sinking of a barge carrying ingots of very special steel sunk at the entrance to a port on the East Coast. Although the wreck lay in relatively shallow water, it was speedily discovered that salvage by the orthodox methods would prove somewhat uncertain, owing to the awkward position of the sunken barge and the difficult tidal and other conditions.