THE CYUNDER, CONCAVES AND BEATER 159 



tion and making the sieves handle a large amount of chaff. 

 This same condition exists when all of the teeth are more 

 or less bent. The cylinder may be moved endwise, as al- 

 ready explained, to give the proper spaces between the 

 teeth, but the teeth must be kept straight Too high speed 

 or too many concave teeth may cause cracking. 



Special Cylinders. To do good work in rice a special 

 cylinder and concave are required with a wider spacing of 

 the teeth than the regular ones. This gives more clear- 

 ance between the cylinder and concave teeth and, together 

 with a reduced speed, prevents the cylinder from cracking 

 the rice. A special cylinder and concaves are also made 

 for threshing peas, beans and peanuts. Either of these 

 special cylinders may be put in any Case separator if the 

 concaves and concave circles be changed also. Further 

 information regarding threshing rice, peas, beans, peanuts, 

 etc., is given elsewhere in this book. 



Balancing Cylinders. On account of the high speed at 

 which cylinders run, they must be accurately balanced or 

 they will not run smoothly. It is essential in balancing a 

 cylinder that the weights used for this purpose be placed 

 where the deficiency of weight exists. The shop practice 

 is to rest the journals of a cylinder on level ways and put 

 weights under center bands until the cylinder will stand at 

 any point on the ways. The cylinder is then put in a frame 

 having narrow, loosely fitting wooden boxes and run at a 

 high speed. The parts of the journals extending beyond 



