FARM MACHINERY 261 



means of the bolts which hold it in place and by the use of 

 liners under the edges of the cap. 



It is to be expected that the severest wear will come upon 

 the pitman. The pitman bearings are difficult to lubricate. 

 A mower which does not provide for adjustment and replace- 

 ment of the wearing parts of the pitman and crank is not 

 modern. Owing to the difficulty of keeping adjustable parts 

 tight, the crank pin box is usually made of solid metal, lined 

 with brass or babbitt, and capable of being replaced at small 

 expense. 



Provision is made in every modern mower for the replace- 

 ment of the wearing parts of the cutting mechanism and for 

 their adjustment to the fullest extent. This statement refers 

 to the sickle or the sec- 

 tions of it; the guards or 

 their ledger plates, which 

 provide one-half of the 

 cutting edges; the clips 

 which hold the knife 

 over the ledger plates; 



j ,, . i , Fig. 163. A side-draft mower. 



and the wearing plates 



which support the rear edge of the sickle. All of these 

 parts are subject to rapid wear, and even when made of the 

 best materials they must be replaced several times during 

 the life of the mower. It is not an uncommon matter to 

 find that a mower has been discarded when it could be made 

 practically as good as new by the replacement of parts whose 

 cost is but a small part of the whole. 



The cutter bar of a mower should be carried as far as pos- 

 sible upon the main truck, in order to reduce the draft due 

 to dragging the bar. This is usually accomplished by suit- 

 able linkage and springs which may be adjusted in such a 

 manner as to carry all of the weight, except enough to keep 



