I 8 SCIENCE OF THRESHING. 



CYLINDER TEETH. 



The cylinder teeth are made so as to be easily 

 replaced when worn out. The forward side of each 

 tooth is curved slightly. 



If perfectly straight, it has a tendency to carry the 

 straw into the machine too rapidly. On the pther 

 hand, if worn too much it retards the passage of the 

 straw into the machine, thereby interfering with the 

 feeding. The cylinder should be adjusted so the 

 teeth will pass midway between the teeth of the 

 concave. If permitted to have too much side play, 

 or to run too close to the concave teeth, the teeth will 

 crack the grain and chop the straw up, and at the 

 same time, will permit heads of grain to pass 

 unthreshed through the wide openings which occur 

 opposite the narrow intervals. The teeth sometimes 

 become loose and cause delay. This is especially 

 true of new teeth when first inserted, as they do not 

 always fit perfectly, and the strain to which they are 

 subjected when the straw becomes compressed in 

 moving through, makes them move a little in the 

 bars. Accordingly, new teeth should be watched 

 carefully when first inserted and tightened up until 

 they are well seated, when they will stay in place. 

 Much time will be saved by going over the cylinder 

 each day and tightening up the new teeth. Many 

 devices have been used to keep the nuts from working 

 loose, some of which have considerable merit. 

 Wooden bars have been used inside of the cylinder, 

 the natural spring of the wood permitting the teeth 



