8 4 



FARM MACHINERY 



is determined by (i) the line of draft, (2) the angle of 

 gangs, (3) the curvature of the disk blades, (4) the 

 weight of the harrow, and (5) the sharpness of the 

 blades. 



123. The cutaway or cut-out disk harrow. As may be 

 judged from the name, portions of the periphery of the 

 blade of this harrow are notched out, allowing the re- 

 maining portions to penetrate the ground to greater 



FIG. 56 A SINGLE-LEVER CUTAWAY DISK HARROW 



depth. The entire surface, however, is not so thoroughly 

 pulverized as with the full-bladed disk. It has a dis- 

 advantage of being hard to sharpen. The cutaway har- 

 row seems to be especially adapted to work among stones 

 and may be used to cultivate hay land. 



124. Spading harrow. This type of harrow has blades 

 curving at the ends, forming a sort of sprocket wheel, 

 with the cutting edges out. It works much like a cut- 

 away. To sharpen it the blades must be separated and 



