184 SCIENCE OF SUCCESSFUL THRESHING 



the two-inch lip sieve, D, should be used as a chaffer. Or- 

 dinarily, the three-eighths inch lip sieve, G, will do nice 

 work as a shoe sieve, and it will remain clean with little or 

 no attention. It should be placed in the second notch at 

 the fan end and third hole at the rear, from the top in 

 both cases. When " white-caps," (as kernels with chaff 

 adhering to them are called) are numerous, the fifteen- 

 sixty-fourths inch round-hole sieve, H, is the best for re- 

 moving them. It should be placed in the second notch and 

 third or fourth hole. Sometimes these two sieves are used 

 together, in which case the former sieve, G, should be 

 placed in the first notch and third hole and the latter, H, in 

 the fifth or sixth notch and the fifth hole. 



For a cheat screen, either the one-fourteenth by one- 

 half inch oblong hole, L, (regular), or the one-sixteenth 

 by three-eighths inch, K, is suitable, depending upon the 

 size of the kernels of wheat. For cockle, the five-thirty- 

 seconds inch round hole screen, I, is the right size. 



Turkey Wheat. Some varieties of wheat, such as the 

 "Turkey," which is raised extensively in Oklahoma, is very 

 difficult to knock out of the heads and often six rows of 

 concave teeth will not thresh it clean from the straw. In 

 this case, one or more three-row concaves of corrugated 

 teeth are necessary. For such grain, the cylinder speed 

 should be kept fully up to the stated number of revolutions 

 or even higher, in which case pulley 5582T should be used 

 as explained for barley. 



