THE WONDERS OF LIFTING MAGNETS.

Ohinemuri Gazette, Volume XXVII, Issue 3600, 29 March 1916, Page 4

THE WONDERS OF LIFTING MAGNETS.

WHAT A BOY'S TOY HAS BECOME.

Although the lifting magnet *s by no means new, during the last two or three years in particular its uses have 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. Frank. M'Clure points out in a paper the toy magnet ol 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 pig»" at the furnaces, also as a gigantlt 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 fore© despite,th# wooden coverings of the kegs. Esver> two or three men are sometimes lifted from the ground, their feet resting upon a metal sheet j 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 con-, nected by service wires. The winding is, of course, insulated. When thf 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 ofl, 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 "skul] 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 08 and the "skull cracker ball" has fallen, the magnet again picks it ut easily arid quickly without any assistance from any one on the ground

As a rule, a man on the ground is not necessary where a lifting magnet Is employed, for the reason that there are no chains, slings, or hoisting blocks to be fitted about the weight to be lifted. However, there are 1 a few instances where a ground man facilitates the work of the magnet. One of these is the lifting ol an ingot, say, of 6,p00 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 righl olace.

Instead of the round magnet just lescribed, a rectangular magnet is lsed 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 press 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 ■in 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 V afforded in the lifting of a very long metal sheet by one nJagnet applied at tha 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.

The use of the lifting magnet makes it possible to pile scrap iron in storage piles of unusual height with c?.r\ ( It is not uncommon to see storage piles of this kind 25 feet high, aid the work of piling it is done with great'rapidity. In loading from was*-\ gons to storage piles, the work of hours when done by hand is reduced to a few minutes by the use of th? magnet.

With the 52-inch magnet, 600 to 800 tons of scrap are easily handled in a day of twenty-four hours at an openhearth furnace, even when four hours,are allowed for delays. When thus operated day and night, th< 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 "situll cracker balls" weighing 30,000 to 50,000 pounds. — " Popular Science Sif tings.'*

Critic (as the composer plays his last piece): "Very fine indeed. But what is that passage, which ma':c the cold chills run down the back?"

Composer : "That is \vln;ro th? wanderer has the hotel bill t:r.i g'J to him."