THE CYLINDER, CONCAVES AND BEATER 1 57 



secure it, and slide it against hub of cylinder head. The 

 holes in the ironsides are slotted to allow for this end 

 adjustment and also to permit the moving 1 of the cylinder 

 in case the cylinder teeth do not come exactly between the 

 concave teeth. Do not crowd cylinder box so hard against 

 the cylinder head as to cause danger of heating. It is best 

 to leave about 1-64 of an inch end play. 



Tracking of Teeth. All regular Case 2O-bar cylinders 

 have five teeth which pass in the same space between the 

 concave teeth, during one revolution, "five teeth tracking" 

 as it is called. The 12-bar cylinders have three teeth 

 tracking. 



Cracking Grain. The cut on the following page is full 

 size and shows the actual distance between the concave and 

 cylinder teeth of the Case regular cylinder. It is shown to 

 emphasize the importance of having the cylinder properly 

 adjusted endwise and of keeping the teeth straight. Sup- 

 posing all the teeth to be straight and that the cylinder be 

 moved 1-16 of an inch to one end. Then instead of there 

 being 1-8 of an inch space between the cylinder and con- 

 cave teeth on both sides, the cylinder teeth would be 3-16 

 of an inch from the concave teeth on one side and only 

 1-16 of an inch from them on the other. This condition 

 of affairs would allow the heads to slip through without 

 being threshed on one side of the teeth and on the other 

 would crack the grain and cut up the straw, thereby con- 

 suming much power, increasing the difficulties of separa- 



