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276 THE MARINE REVIEW June, 1919 ---- 7 7 ; molds, clamps are wedged at frequent intervals to take all the lifting stress in the mold when the molten metal is poured. A runner box is placed on the top of the mold and feeds a num- ber of sprues. These lead directly to the falls of the cylinder. The metal flows to the bottom along this wall and feeds up into the other por- tions of the mold. The tops of the cylinders are pro- vents are plentiful. Separate vents for each core section are carried to the outside of the mold. A 25 per cent steel mixture is used in these castings and about 40 tons of this metal is poured daily. The cylinders are generally poured d between 2:30 and 3:30 p. m. They vee -- WOM = ore allowed to remain in place until é cis the night shift comes on at which time they are taken to the shaking- out floor. After the castings are shaken out, the flasks are sufficiently cool to be used again the next morn- ing. core for the piston-valve chamber times in which the superfluous The castings are cleaned of sand requires careful setting. To save metal from castings is poured. Cores by pneumatic tools after which they time in setting the cores in place, are baked by natural gas in under- are immersed in a_ sulphuric acid a number are assembled on one ar- fired ovens, each provided with a _ pickling solution for 24 hours before bor. The intermediate cylinder, how- single burner. Pyrometers are used removal to the machine shop for in- ever, is the most difficult to mold, to regulate the heat which insures gpection. Each cylinder before it is The cores for the ports are made in properly baked cores. accepted for machining is sealed and sections, split horizontally, to facilitate The low-pressure cylinder is the subjected to a hydrostatic test. The setting. The lower half is placed simplest to mold as the cores are pressure which must be sustained in the drag before the first cheek 1s pot so complicated. The barrel core without leaks developing is 300 pounds in place. The cheek is then set and jg equipped with a chill flange at the to the square inch for the high-pres- the upper section of the port core top, the object of which is to pro- sure, 150 pounds for the interme- is set in place. vide against segregation between the diate and 50 pounds for the low-pres- Intermediate cylinder molds are as- cylinder walls and the head. After sure cylinder. This inspection is sembled before 2:30 in the afternoon. flasks are assembled into complete made under the supervision of inspec- The molders begin work at 6 tors from the Emer- p.m. © Cate is exercised in . gency Fleet corpora- every core setting operation, a G tion, the American measure absolutely necessary | Bureau of Shipping and if accurate results are desired. | Lloyd's. The base is Used ground core sand, cast in three sections. mixed "witha. small amount of pitch, is em- \ ployed for all of the e ) larger cores in_ this * ' work. Arbors for these cores'; are used. in abundance, a bed of molds for these being in readiness at all FIG. 5--SQUARING THE ENDS OF CONNECTING RODS IS DONE ON THE ENGINE LATHE, BETWEEN CENTERS FIG. 6--ASSEMBLING FIXTURE USED IN LOCATING THE CRANK WEBS DEPENDS IN A GREAT MEASURE TH ON THE SHAFTS AND PINS IN THE SHRINKING OPERATION--ON THIS OPERATION E ACCURACY OF THE FINISHED CRANKSHAFT