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Page:Popular Science Monthly Volume 89.djvu/305

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Popular Science Monthly


��The piston-heads may be cast in the eccentric ring. Sim()iy lay the ring on a piece of paper on a flat surface and pour it full of hahhiu. Two of these are required. -After casting, the center is carefuli\' located with a pair of di\id- ers, after which a 5 i6-in. hole is drilled through it. To cut the groo\e in the pistoii- heads the arrangement shown on this page is used. .\ block of wood has a 5 i6-in. hole iiored through it. A piece of 5 i6 in. iron is threaded on one end and a piston held in place on it by meansof locked nuts. The other end of the iron is run through the block anti bent into the form of a crank.

��was the eccentric mold, except that no ring is used and the hole for the shaft is in the center. .\ hole must be pro- \ided for pouring. When pouring, be certain to have the shaft set square with

, t h e m o 1 d .

D ^ "1 ^Ttr ^[luare up by

the method suggested in the drawing.

The tl\- wheel is made of lead or babbitt. In this case the mold is about 3'4 in. deep and 3 ins. in diame- ter. The shaft should be in the mold when the casting is made.

The bearing support is easily made of cither iron or brass. Bend to shape first and then lay off and drill the holes for the bear- ings. These are short pieces of pipe used for the steam- Drive a nail into the block for the K^-in. chest, ports, etc. Place the shaft chisel and the groove is cut by turning through the bearings, and place the

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��Plate 3. Diagrams showing dimensions of the vari- ous parts of the opposed cylinder steam engine

��the piston and holding the chisel against it. The grooves are cut >4 in. deep.

The piston-rods are worked out from cold rolled steel or brass. Only the one needs the ^s-'ui. notch cut into it as that is for the connecting rod to fit into. The two inner ends of the piston-rods are lapped together and bolted with two } s in. by Jo 'i- stove bolts. A Jg'*'^- hole must also be drilled in the center of the space allowed for fastening the con- necting rod. The pistons are held on the ends of the connecting rods 1)\- means of locked nuts. Note Plate 2.

The connecting rod is .sliown in Plates 2 and 3. I'se 'g in. by i^o in. material, either brass or iron. The curves may be worked out with a file.

The crank wheel is },■> in. thick by 2 ins. in diameter. The mold is made as

��)earmgs in place in the support, when the\- may be soldered in position.

The shaft is shown in Plate 3. It is best made from cold rolled steel although brass will do.

Ha\ing brought all of the details to this jjoint the most interesting part is now to be done.

In a.sscmbling, fasten the connecting rod in position on the piston-rod. I'se a Js-in. rivet for this, but do not make it too tight. Pack the pistons with cotton waste, asbestos packing or soft yarn. Assemble them in position in the cylinders, bolt them together and see that they work smoothly. Next place the shaft in position in the bearings with the eccentric and eccentric ring in place. Fasten the eccentric to the shaft by drilling a small iiole down through both

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