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250 production and is in position to exer- cise more critical and unbiased judg- ment in the matter of quality. If any one part of a marine diesel engine may be said to be the most important it is the crankshaft. Steel for it is purchased in the ingot form, with rigid specifications as to manga- nese, silicon, sulphur, carbon and phosphorus content. Only bottom- poured ingots are acceptable, and as high as 80 per cent is cropped off the top to eliminate impurities. On arrival at Beloit all ingots are in- spected for seams or surface defects, and metallurgical and chemical tests are made. Each ingot is numbered before going to the storage yard. A 1000-ton hydraulic press is used for forging the crankshafts. The hydraulic press method, according to Fairbanks, Morse engineers, refines the material at the center of the shaft. _ The billets are forged at about 2000 degrees Fahr., the temperature and forging time being closely regulated by the engineering department in con- formity with the chemical analysis of the billet being worked. After forg- ing, the shaft goes to the crankshaft machine shop where the journals are rough turned, the throw blocks drilled and blocks of metal sawed out. The crank pins, which are in square form, NARINE REVIEW is based upon these standards: Ten- sile strength, 80,000 pounds _ per square inch; elastic limit, 50,000 pounds per square inch; reduction of area, 45 per cent; elongation in 2 inches, 24 per cent; bend test of a 2- inch bar taken from the shaft, 180 degrees without fracture. Connecting rods are die-forged. Every Process Is Controlled The gray iron foundry of the Fair- banks, Morse Co. at Beloit is 454 feet wide and 544 feet long, with four 96-inch cupolas with a total capacity of 80 tons per hour. There is stor- age space for 18,000 tons of sand, FORGING THE CRANKSHAFT FOR A DIESEL ENGINE AT THE BELOIT, WIS., WORKS OF FAIRBANKS, MORSE & CO. are rough turned. The shaft is then inspected and returned to the forge shop for heat treatment. Furnace temperatures are recorded by electric pyrometers placed in a locked room. Lights and deviation meters make a continuous record which is carefully preserved with other data concerning the individual shaft. The heat treatment accorded shafts 10,000 tons of pig iron, 3000 tons of scrap and 1000 tons each of coke and lime. Mixtures are made up and charges weighed under the direct con- trol of the laboratories. A sample of the molten iron from each cupola is analyzed every hour. An analysis is also made of each ladle. To insure the cylinder and cylinder-head castings being hard and at the same time free ( July, 1925 from strains and stresses caused by pouring practice, a special method of curing castings in sand has been de- vised to take the place of the cus- tomary annealing. The special equip- ment of the foundry includes 230 mold- ing machines, 31 traveling cranes and 30 air hoists. Steel parts are finished in one ma- chine shop and the cylinders, pistons and all cast iron and brass parts in another. Special jigs and fixtures have been worked out to effect complete interchangeability. The limits of ac- curacy are at least equal of those governing the finishing of the finest automobile engines. As an example of A LATHE WHERE THE TOOL REVOLVES FINISHING THE CRANKPINS ON A CRANK- SHAFT FOR A 360-HORSEPOWER DIESEL ENGINE the high standards that must be ad- hered to, room temperature is com- pensated for in order to eliminate in- accuracy caused by sag. To make absolutely certain that the crank pins are parallel with the jour- nals a special lathe is employed wherein the crankshaft remains sta- tionary and the tool revolves around the work. Considering that the crank- shafts range from 6 to 10 inches in diameter and frequently exceed 20 feet in length, the following tolerances re- veal, the dependability that is built into them: Axes of journals and crank pins to be paralleled with total of 0.002 inch measured in the length of the crank pin. Variation in axis of any journal from axis of shaft, measured by re- volving shaft in V_ blocks, shall not exceed 0.0015 inch radially measured in the length of the journal. : Avially, center to center of adjacent