84 ROUGH-AND-TUMBLE ENGINEERING 



the same lead when on either center. In the absence of 

 any better tool to ascertain if the lead is the same, make 

 a tapering wooden wedge of soft wood, turn the engine 

 to a center and force the wedge into the opening made 

 by the valve hard enough to mark the wood ; then turn 

 to the next center, and if the wedge enters the same 

 distance, you are correct; if not, adjust till it does, and 

 when you have it set at the proper place you had best 

 mark it by taking a sharp cold chisel and place it so 

 that it will cut into the hub of the eccentric and in the 

 shaft; then hit it a smart blow with a hammer. This 

 should be done after you have set the set screws in the 

 eccentric down solid on the shaft. Then, at any time 

 should your eccentric slip, you have only to bring it back 

 to the chisel mark and fasten it, and you are ready to go 

 ahead again. 



This is for a plain or single eccentric engine. A double 

 or reversible engine, however, is somewhat more diffi- 

 cult to handle in setting the valve. Not that the valve 

 itself is any different from a plain engine, but from 

 the fact that the link may confuse you, and while the 

 link may be in position to run the engine one way you 

 may be endeavoring to set the valve to run it the other 

 way. 



The proper way to proceed with this kind of an engine 

 is to bring the reverse lever to a position to run the en- 

 gine forward, then proceed to set your valve the same 



