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AGRICULTURAL ENGINEERING 



Fig. 124. A cutaway disk harrow. 



the disk to extend half way over the work of the previous 

 round. The merit of this method lies in the fact that the 

 ground is left nearly level, while a single disking will leave the 



ground slightly ridged. 

 When this method is fol- 

 lowed, the disk gang work- 

 ing on the once diskeci 

 ground finds less resist- 

 ance than the gang work- 

 ing in the undisked ground. 

 By setting the gang in 

 the loose soil at a sharper 

 angle, the machine is balanced and the soil pulverized more 

 than otherwise. The two-lever machine also has a decided 

 advantage in hillside work. The tendency of the machine 

 to crowd downhill may be overcome to a large extent by 

 a separate adjustment of the gangs. 



Types of Disk Harrow. Disk harrows are built in 

 three general types, as far as the construction of the disk is 

 concerned. First, there is the full-bladed disk with solid per- 

 fectly round edges; second, the cutaway or cut-out disk, 

 which is like the full-bladed disk except that notches are 

 cut out of the edge, leav- 

 ing short points to enter 

 the ground; third, the 

 spading disk harrow 

 which consists of a series 

 of sharp blades curved at 

 the end and made up into 

 a sort of sprocket wheel. 



For average conditions the full-bladed disk is the best- 

 It has a greater pulverizing action, is stronger, and is more 

 effective in cutting up trash and stalks. Another very im- 



Fis 



125. A spading disk harrow. 



