Concerning Hammers

To most persons a hammer is simpiy hammer, but evei-y mechanic knows that there is a great variety of hamtiicrs, irom the tiny lump of steel with which the watch-maker taps the mandril of a balance wheel to the huge trip hammer under which tons of hot iron arp. molded into shane. The hammer, n fact, playa an important part in ine mechanic arts, each one presenting lts peculiar form, size, weight, and material. In some trades there is great skill and dcxterity required in the use of the hammer. Any one who has seen the operation of riveting a boiler has admired the sleight of hand with which _ the strikers round up the head of a rivit in less time than it takes to write about ït. The blows follow one another with wonderful accuracv and rapidity, and when the rivet hcad is finished ït looks as sniooth and regular as if it had been cast in a tmrnished mold. Take even the proeess of driving an ordinary nail and it is remarkable what a difference there is in the method of a novice and that of a carpenter. The one hits one side, often bends or breaks the nail or bruises the finger that holde it. The carpenter hits with precisión and drives the nail home with well-directed blows. The deft hammering of coppersmiths is proverbial, pounding metal into any required shape. lhe sopper plates that are nsed by engravers are hammered hard in long strips by the use of large steel hammers wrth faces as smooth as that of a mirror. I he most accurate hitting is required in Uus process, because the hammer face is flat and must be held perfectly level to avoid cutting deep gashes in the plates. When it is necessary to make bevels on these plates, a skilied workmau will make a bevel with a hammer in a few minutes that would require hours ïf made by filling and polishing. Silversmiths lcarn to be very expert in the use of the hanimer. Spectaole tnakers can take the temples of a pair of ladies' spectacles and temper them by dexterous planishing between hammer and anvil. A blacksmith always has an assortiment of hammer with which to shape the ductile iron. File cutters are required to use hammers with great judgraent. Each tooth in a hand-made file is made by the burr raised by tapping a chisel neia to tno soft file." Alter each blow the chisel is set up against the burr of the last stroke and another burr is raised, and so on until the file is finished. The force of the blow nieasures the size of the burr raised, so that the regularity of the file depends upon the evenness of the hammer stroke. Many files are made by transferring processes by maehinery, but the hand-made files command the hio-hest price, while with many peculiar forms of files the hand work is indispensable, and the regularity of hammer work a necessity. One of the most difficult jobs to be done with the bammer is to straighten large ilat plates of metal. An expert workman will here do, with a few strokes of the hammer properly directed, work that a non-expert cannot do at all. Indeed, without great skill the attempt to straighten plates with a hammer eenerally, resulta in making the crookedness worse. ; The goldbeater's hammer is wielded day by day by the trained hand, althouo-h an hour of it would fatigue the novice. The calker has a peculiarly long hammer. The ax and the adze are but sharpened hammers. Machinists use great eopper hammers for work where they wish to strike blows without marrino- the object struck. the queerest hammers m use is a magnetic hammer. There was once a Yankee peddler who used one of these to a great advantage. He was peddling a fancy soap. He would go into a store; pull out his advertising card, "But my unequalecl soap, ami uuiuie the astonishing storekeeper coulcl rénionstrate he would tack up one of ms cards on a rafter or wal! where it could not be taken down without a step ladder. The way he did it was to hold up his card to the required spot with one outstretc&ed arm, standing on tiptoo. He had a magnetized hammer with a handle, and in his mouth a few tacks. He put one tack on the hamuier, point ontward, and with one tap sunk it into the required place to secure his card out of reach. Recently, in South Brooklyn, i tall bill poster pursued this plan of posting advertisement cards on telegraph poles so high that it ïequired the line men to climb up the poles to get cards down.