1 6 SCIENCE OF THRESHING. 



slower which will thoroughly dislodge the kernels 

 and not break the straw so badly. In damp and 

 tough grain a faster speed may be used if necessary 

 to thresh the straw clear of kernels. 



On account of the cylinder being so heavy and run- 

 ning at so fast a speed, it should be kept in perfect 

 balance, as it greatly adds to the smooth running of 

 the machine. When the cylinder is out of balance, it 

 is easily detected by the jarring or vibrations in its 

 vicinity. By placing the hand upon the frame work 

 of the machine near the cylinder boxes or bearings, a 

 peculiar jarring may be plainly felt when the cylinder 

 is not true. The side on which this is most evident 

 will indicate the end of the cylinder which is at fault. 



If permitted to run out of balance, the cylinder 

 will have a tendency to cause its journals to heat and 

 wear out rapidly, and also to flatten the cylinder shaft 

 on the side that receives the wearing strain. A 

 smoothly running cylinder requires a minimum of 

 power to drive it, as whatever force is used to cause 

 the vibration is so much power lost, or work done for 

 nothing. The working and lasting qualities are also 

 lessened, if allowed to vibrate, as every vibration has 

 a tendency to loosen the framework of the entire 

 separator. 



A cylinder may be put in balance by removing it 

 and placing it with its journals resting on two parallel 

 straight edges, such as carpenters' squares set up 

 edgewise. The squares or straight edges should first 

 be trued up with a spirit level, and may be held in 



