. Railway mechanical engineer . be kept in stock and will meet therequirements better than a large variety of shapes and sizes. For punching holes in angle irons or to meet special re-quirements, it may be necessary to make longer punches orhigher dies. These, however, can generally be made witlithe same sized bodies and to fit the same holders. Dies are at times made with a tlattened side for a setscrew to rest against for holding in the die block. With diesmade correct to size this cannot be considered necessarv, asa die will rarely lift in the die block. The set screw maybe an advantage to
. Railway mechanical engineer . be kept in stock and will meet therequirements better than a large variety of shapes and sizes. For punching holes in angle irons or to meet special re-quirements, it may be necessary to make longer punches orhigher dies. These, however, can generally be made witlithe same sized bodies and to fit the same holders. Dies are at times made with a tlattened side for a setscrew to rest against for holding in the die block. With diesmade correct to size this cannot be considered necessarv, asa die will rarely lift in the die block. The set screw maybe an advantage to prevent the die turning or coming , this is a question. It is very essential that punches and dies be made correctto size and true, so that in the event of removing either itshall not be necessary to readjust the die block to line upwith the punch. Generally the hole in the die block shouldbe about .OOo in. larger than the nominal size of the die,and the dies should be made to the nominal diameter to Fig. 3—Bolle. Punch Hold about .005 in. less. The puiith should Ije true and the topsurface square with the body to prevent throwing the cuttingedge out of line and necessitating a readjustment of the die. ^RE WRENCHES AND SOCKETS One annoying problem is that of keeping up the supplyof wrenches, air motor sockets, etc. necessar\ for driving stay-bolt ta|)S, reamers and applying staybolts. This is aggravatedby the variety of sizes required. If the number of these sizescan be reduced, the conditions will bf improved both in thetool room and the rest of the shop. For example, the squareshank on a ?^-in. stayljolt tap is generally made 9/16 taps do not require a great amount of power to drive MECHAXICAL ENGINEER Vol. 92, No. 6 and ai thcv do iiol bottom tlicy do not receive the abuse in-cident to bottoming. Without a doul)t staybolt taps of J^-in.,15/16-in., 1-in. and 1 1/16-in. can all l)e made with 9 shanks, and the IJ/g-in., 1 o 1
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectrailroadengineering
