130 SCIENCE OF SUCCESSFUL THRESHING. 



handled auger wrench arid then driven in and tightened 

 again, but they are liable to get loose the first few days unless 

 special attention be paid them. If a tooth be allowed to re- 

 main loose for any length of time the hole will become so 

 misshapen that the tooth cannot be kept tight thereafter. The 

 teeth should be kept straight, not only so they will not 

 strike, but also so that they will pass at equal distances from 

 the concave teeth on both sides. 



Cylinder Speed. It is very important that the cylinder 

 run at the proper speed. If run too fast, there is danger of 

 cracking the grain, and if run too slowly, it will not thresh 

 clean. Then, too, the work of separation and cleaning is 

 very much easier if the cylinder runs at the proper speed 

 and is never allowed to get below it. The motion must be 

 uniform if the best results be expected, for every time it is 

 allowed to get much below or above the correct speed, the 

 separator will waste grain. With the regular pulleys, the 

 large 2O-bar cylinder of the Qase separator should run at 

 750 revolutions per minute to give the proper speed to the 

 other parts of the machine. The regular speed of the small 

 or 12-bar cylinder is 1075 revolutions per minute. In thresh- 

 ing tough rye or oats, the cylinder is subjected to more work, 

 and often runs too slowly if attempt be made to maintain 

 the normal speed, therefore, the cylinder should run faster 

 than usual, say, 800 for the 2O-bar and 1150 for the 12-bar, 

 in order that the other parts of the machine may run up to 

 their usual speed. Some grains and legumes require special 



