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Fuly, 1919 thrust shaft are cast iron, lined with bearing metal. They are equipped with a composition half-gland for holding | oil. : The first step in machining the base for the thrust bearing consists of finishing the flat surface on the bottom. It is essential that this sur- face be planed perfectly true, other- wise the 'casting will be distorted when it is bolted to its foundation. This error could, of course, be cor- rected in the assembling' operation by means of shims but the experience of the Hooven, Owens, Rentschler Co. 'has i proved. that the rapid. and 'Speeds Up Production 'HAT it is economical to ma- chine many parts at one op- eration whenever possible while building heavy machinery, such as marine engines, is graphically shown by several illustrations in this ar- "ticle, which is the secund of a series describing manufacturing op- erations on marine engines at. the _ plant of the Hooven, Owens, Rent- _schler Co., Hamilton; OO. . | The previous instailment, which appeared in the June issue, . de- scribed manufacturing operations on, heavy units such as bed plates, cal- uns, cvlinders, crankshafts, con- necting rods, etc. The present in- stallment describes manufacturing operations on many .of the lighter units such as the value. gear, bear- ings, air pump, crosshead, etc. The concluding article, which will be published in August, will describe assembling operations... These arti- cles, secured exclusively. for. THE Marine Review, give a litile in- sight into the tremendous work American manufacturers. faced . in promoting the winning of the war by adapting existing plants to war production on a quantity basis. satisfactory assembly of various units depends largely on the accu- racy of the previous machining opera- tions. After the base is planed the seats for the end journals and the flat suridce .. for "ldeating » the: thrust rings, are carefully finished by plan- ing. Then the end bosses for the side rods are faced. Holes for the foundation bolts are next drilled. This work is done on a radial drill and the holes are located by means of a jig to insure accurate duplication. The holes for the side rods are also drilled and reamed in a jig which locates from the end bearing seats. In machining the thrust rings, the first step is to rough out both side THE MARINE REVIEW. surfaces. This operation is generally done on a vertical boring mill. Next the wearing surfaces are formed by casting bearing metal in place. This metal, after cooling, is thoroughly hammered, or peened. The object of this is twofold: It densifies the metal and seats it securely in place. In the design of the thrust rings i i i | 339 lating pipes completes the machine work. The thrust shaft is machined from a solid steel forging. The first step is to center the piece accurately, after which it is mounted in the lathe and roughed out all over. It is carefully recentered before the finishing opera- tion, due to the fact that the sides FIG. 16--HOW THE HOLES FOR PINS ARE DRILLED IN LINK BARS--A JIG IS USED FOR LOCATING THE HOLES AND TWO BARS ARE DRILLED AND REAMED SIMULTANEOUSLY. seats are provided for anchoring the bearing. metal in place. Next the bearing surfaces are finished by turn- ing on the boring mill. In this oper- ation it is essential that both sides be parallel to insure a good bearing after the unit is set in place in the assembly operation. The bottom of the bearing is now planed square with the bearing surfaces, after which holes for the locating studs are drilled by means of a jig. Drilling and tap- ping the holes for the water circu- y : of the collars and the main journals must stand square with each. other. As..the piece is located' from the centers on this operation, it is appar- ent that they must be true. The heavy roughing cuts distort the cen- ters somewhat which makes recenter- ing before the finishing operation necessary to insure ascurate results. The journals and the sides of the collars receive an additional finish by polishing with emery and oil. This insures smooth running surfaces. The