THE VALVE-GEAR. 



73 



centers at the factory, and by applying one of the company's 

 trams, as indicated in Fig. 22, they may be readily placed 

 on either dead-center. It may be necessary to scrape 



off the paint to find the 

 prick-punch marks on the 

 frame and on the crank-disc. 

 The tram shown in the illus- 

 tration measures eight and 

 three-sixteenths inches be- 

 tween the points, which size 

 FIG. 23. TRAM ON DISC. has been used by the "Case" 

 company for many years. It will be seen that a "Case" en- 

 gine may be put on its dead centers by using a pair of divid- 

 ers set to this distance, but they do not serve the purpose as 

 well as the tram. The following method of finding the dead 

 centers is the one used at the factory, and is generally used 

 on all styles of engines. To put it into use, first take up all 

 lost motion in the connecting-rod brasses, crank-shaft bear- 

 ing and cross-head shoes. Then turn the engine until the 

 piston lacks an inch or so of completing its stroke. Make 

 a prick-punch mark at any convenient place on the cross- 

 head (see Fig. 24), insert one point of the tram in the mark 

 and with the other point, make a scratch on the engine frame 

 to locate a second prick-punch mark. The tram points 

 should now measure the exact distance between the two 

 marks and when applied should be nearly paral 1 el to the 



