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280. RE iaiaiiai THE MARINE REVIEW fan Wr i FIG, 11--CYLINDERS ARE BORED ON A VERTICAL BORING MILL TO INSURE THEIR BEING ROUND WHEN IN THE POSITION IN WHICH THEY OPERATE-- CYLINDER SHOWN IS A LOW PRESSURE--THE ROUGHING CUT HAS JUST STARTED . bored .at- one .setting. For this rea- son, the holes will align exactly, a condition necessary in making up a crankshaft that will run true when finished. The holes are accurately sized by means of micrometer gages. This is essential to insure success in FIG. 12--VIEW IN the shrinking operation that follows. Before the two cranks are taken apart, they are keyseated on the slot- ter to accommodate the key that po- sitions them on the crankshaft. From this, it is clear that the two holes im een, crank, 4s well as the :key- THE MAIN MACHINE SHOP--THE MACHINE AT THE EXTREME RIGHT IS A HORIZ PRESSURE CYLINDER seat, will align absolutely as all the work on both cranks was done simultaneously. The crank pins are accurately turned tO "size On an engine Jathe: "Tue portions that are to be shrunk in the left oversize, webs are the amount ONTAL BORING MILL WORKING ON A LOW