THRESHING WITH REGULARLY EQUIPPED SEPARATOR. 153 



the machine is doing, what changes in the adjustment or 

 arrangement of concaves or in the speed, will improve the 

 work. For example, if the wheat be thoroughly knocked out 

 of the heads and there be an excessive amount of chaff and 

 chopped straw, it would be well to see if the kernels could 

 still be threshed clean from the straw if the concaves were 

 lowered a notch or two, or perhaps one filled concave re- 

 placed by a blank or else the speed lowered slightly. If any 

 of these changes were made, the work of the machine as a 

 whole would be improved, for separation and cleaning are 

 made easier by reducing the amount of chopped straw. 



The adjustable-chaffer, chaffer-extension and shoe-sieve 

 can be best adjusted while the machine is running, the oper- 

 ator noting how much chaff each is handling, how the wheat 

 is cleaned and the amount of tailings being returned, as ex- 

 plained in Chapter V. The adjustable shoe-sieve should 

 be placed at, or very near, the top, at the fan end and in the 

 fourth hole from the top at the rear end. 



When the separator is equipped with common sieves, the 

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

 arily, the three-eighths inch lip sieve, G, will do nice work as 

 a shoe sieve, and it will remain clean with little or no atten- 

 tion. 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 removing them. It should be 



