210 SCIENCE OF SUCCESSFUL THRESHING 



nailing the leather again to the first pair before cutting off. 

 Trim the edges even with the rim of the pulley. 



Riveted Covers. The same method of stretching the 

 leather by means of a clamp may be used on pulleys with 

 riveted covers or they can be covered in the following man- 

 ner : Soak the leather in water for an hour. Cut off one 

 end square, and rivet it on. Then draw the leather around 

 the pulley and mark the next two pairs of holes. Punch 

 holes in the leather a little back of the marks made by the 

 first pair of holes and a little farther back of the marks 

 made by the second pair of holes. Insert the points of two 

 scratch awls through the second pair of holes in the leather 

 and into the corresponding holes in the pulley rim. Using 

 scratch awls as levers, draw the leather very tight and the 

 first pair of rivets may be easily inserted. Move the awls 

 to the third pair of holes, insert the second pair of rivets 

 and so on around the pulley. The tines of an old pitch- 

 fork drawn down a little at the points and tempered make 

 very suitable scratch awls for this purpose. 



The Belting of the Separator should be carefully looked 

 after, as the working of the machine depends in a large 

 measure upon the condition of the belts. The pulleys must 

 be in line, to insure the belt running on them its full width. 

 Where the shafts are parallel, a belt will always run to the 

 tightest place or where the pulleys are largest. For this 

 reason, all pulleys on the separator are made larger in the 

 middle, "crowning" as it is called, so belts will tend to 

 run in the center. 



