.76 



SCIENCE OF SUCCESSFUL THRESHING. 



strong enough to shear off the' points of the set screws which 

 secure the eccentric. 



Besides the marks on the eccentric, there are marks on the 

 valve-stem and its stuffing-box, in order to make apparent 

 any change in the length of the valve-rod or the eccentric- 

 rod. To use these marks, however, one should have one of 

 the Company's valve-rod trams. This is shorter than the one 

 used on the crank-disc and measures exactly four and three- 

 sixteenths inches between points. It is used as shown in 

 Fig. 24. There are two marks on the valve-stem and they 



should be on top. When the 

 reverse lever is at the rear end 

 } of the quadrant, (i. e., the road 

 motion), and the engine is 

 placed on one of its dead cen- 

 ters, the valve-rod tram should 

 drop into one of the marks, and 



FIG. 25. TRAM ON VALVE-STEM. 



when the engine is placed on 



its other dead-center, the tram should drop into the other 

 mark. If the tram points do not drop into the marks, the 

 eccentric rod should be adjusted as to length until they do 

 or else the valve must be entirely re-set as explained below. 



Setting the Valve on Engines with Woolf Reverse. After 

 having taken up all the lost motion on the valve-gear, main- 

 bearings, crank-pin and cross-head pin and shoes, and being 

 provided with the tram for placing the engine on its dead- 

 centers, as explained, proceed to set the valve as follows ; 



