THE WONDERS OF LIFTING MAGNETS.

Ohinemuri Gazette, Volume XXVIII, Issue 3793, 13 July 1917, Page 4

THE WONDERS OF LIFTING MAGNETS.

WHAT A BOY'S TOY HAS BECOME. Although the lifting magnet is by no means new, during the last two or three years in particular its us«i bave multiplied to such an extent that many new and widely different types have been designed to handle the multitudinous shapes of metal produced. The magnet is fast becoming adopted to handle all forms of iron and steel from iron dust or scraps to weights of 20,000 pounds. In fact, the world's largest magnet will lift as much as 50,000 pounds. Thus, Mr. W. Franlc M'Olure points but in a paper the toy magnet ot our boyhood is converted into a useful instrument in the workshop. Used at first chiefly in carrying iron and steel to and from cars or storage piles, the lifting magnet is now utilised in breaking up imperfect castings, in holding sheets o> metal in position while being revited in the construction of ships, in lifting a "sow and pigi" at the furnaces, also as a gigantk broom to sweep both the large and small pieces oi iron, and in many other ways. A half-dozen kegs of nails may be seen travelling through the air, held by magnetic lines of force despite th« wooden coverings of the kegs. Eveu two or three men are sometimes lifted from the ground, their feet resting upon a metal sheet, which is firmly held by the magnet. Lifting magnets are usually operated from an electric overhead travelling crane, but they may also be operated from a locomotive crane. Within the magnet are coils with which the service wires are connected just as an incandescent lamp is connected by service wires. The winding is, of course, insulated. When tin magnets handle hot. material, they are wound with fireproof wire. Th« novements of the magnet are directed by the operator of the crane. The opening or closing of a switch turning the electricity on or off, causes the magnet to pick up or r» lease its load. The 20,000-pound weight referred tc as a typical large lift made by magnet power is in the form of a "skull cracker ball," used to break up imperfect metal that is to be remelted. The magnet used for this lift is 55 inches in diameter, and its weight 1,800 pounds. It requires 4 feet 6 inches head-room. When this great weight has been lifted high in the air, and the current is turned off and the "skull cracker ball" has fallen, the magnet again picks it ut sasily and quickly without any assistance from any one on the ground As a rule, a man on the ground it not necessary whera a lifting magnei ts employed, for the reason, that there are no chains, slings, or hoisting blocks to be fitted about th« weight to be lifted. However, there are a few instances where a ground man facilitates the work of the magnet. One of these is the lifting of an ingot, say, of 6,000 pounds. If a ground man places the magnet, two of these ingots can be lifted ; otherwise only one at a time. • For if two Ingots are to be lifted simultaneously, they must be in proper position, on account of their weight, for the magnet to grip them in their right place. Instead of the round magnet just lescribed, a rectangular magnet is ised in lifting a "sow and pigs" at the furnaces. When thus lifted from the sand they are not white hot, but yet strongly heated. Hot metal m the form of billets is also lifted by a special magnet to a conveyer, and taken to where it is sheared or cut into shorter lengths or to where it may be stamped out by a hydraulic presß into car wheels and finished upon a lathe. A rectangular type of magnet is also used for holding steel plates in place to be riveted tn the construction of ships. For two or three years past a number of these magnets have been in use at the imperial shipyards in Yokohama, Japan. Another interesting sight is afforded J In the lifting of a very long metal ] sheet by one magnet applied at the sheet's centre. The ends of the sheet may dip down to an angle of 45 deg. and still the sheet be held tightly by - the magnet. I The use of the lifting magnet makes It possible to pile scrap iron in storage piles of unusual height with ease. It is not uncommon to see storage j piles of this kind 25 feet high, aud the work of piling it is done with great'rapidity. In loading from waggons to storage piles, the work of hours when done by hand is reduced to a few minutes by the use of the < magnet. < With the 52-inch magnet, 600 to . 800 tons of scrap are easily handled in a day of twenty-four hours at an ©penhearth furnace, even when four : hours are allowed for delays. When thus operated day and night, the magnet takes the place of fourteen labourers. If operated with a specially fast crane, the amount handled ( Is still further increased. The magnet mentioned as the most powerful in the world is 60 inches in diameter and will handle "skull cracker balls" weighing 30,000 to 50,000 pounds. — ••' Popular Science Sittings."