TILLAGE MACHINERY JTI 



the coulter is made to ciit I inch or more outside the 

 landside, thus increasing the load upon the plow, it can 

 be made to scour when giving difficulty in this respect. 

 When plowing among roots the plow is enabled to run 

 over rather than underneath large roots by inclining the 

 knife coulter backward with its point below the point of 

 the plow; otherwise the knife coulter must be set with 

 the lower point well ahead. 



106. Scouring. Some soils are of such a nature that 

 a plow can be made to scour only with difficulty. This 

 is true especially of soils in the Middle West. In other 

 localities plows give little trouble in this respect. When 

 the plow is at fault, poor scouring may be due (i) to poor 

 temper. In this case the share and moldboard are not 

 hard enough to take a good polish, and hence will not 

 scour well. These parts should be so hard that they can 

 barely be scratched with a file. (2) To poor grinding. 

 Sometimes hollows have been ground into the moldboard, 

 over which the furrow slice presses so lightly that not 

 enough pressure is given to cause the spot to scour. This 

 may readily be tested by carrying the tips of the fingers up 

 the plow quickly, from the edge of the share in the direc- 

 tion the soil moves. (3) To a poor fitting, i. e., where the 

 joint between the share and moldboard is not smooth. 

 A remedy for this is procured by shimmering the share 

 up or down with small pieces of pasteboard. (4) To the 

 edge of the share not being level, making a low spot back 

 of the edge. This is usually caused by a warped .share. 

 (5) To poor setting. The plow must be set as previously 

 described. 



107. Sharpening steel shares. It is recommended by 

 some manufacturers that until necessary only the ex- 

 treme point of a share be heated to put into form, the 

 edge being sharpened by grinding; but when necessary 



