FARM MACHINERY 



217 



portant advantage of this type is the convenience of sharpen- 

 ing. These disks may be sharpened to a good edge by means 

 of any of the disk sharpeners which will do 

 good work. About the only way that the 

 notches of the cutaway disk may be sharpened 

 is by removing all of the disks and grinding 

 them to edge on an emery wheel. The blades 

 of a spading harrow are sharpened by heating 

 each individual knife and drawing out the 

 edge with a hammer while hot. 



The cutaway harrow is very deceiving in 

 the amount of work it does. The blades 

 sprinkle the soil over the surface in such a way 

 that the unstirred soil underneath is hidden. 

 This harrow has a decided advantage in cul- 

 tivating and renovating old pastures. Where 

 the full-bladed disk would cut the stubble up 

 and destroy it, the cutaway will loosen the 

 soil in such a way as to stimulate growth. 



In the amount of work done, the spading 

 harrow is much like the cutaway. The prin- 

 cipal 'advantage of the spading harrow lies in 

 its ability to work in wet ground, when the full-bladed 

 disk would be sure to clog. 



The "plow cut" disk has a bulged or raised center, it being 

 claimed that the soil will be more nearly turned over when 

 coming in contact with this center. The name might imply 

 some sort of plow action, but the work of this type, as far as 

 the writer has observed, does not differ much from the 

 ordinary disk harrow. 



Alfalfa Harrow. The alfalfa harrow is a special tool 

 with sharp spikes arranged as disks in the frame of a common 



Fig. 126. A 

 plow-cut disk 

 used on disk 

 harrows. Note 

 the raised 

 center. 



