212 SCIENCE OF SUCCESSFUL THRESHING. 



wise fits properly may be made tight by putting a strip of 

 tin or sheet-iron between it and the bottom of the way in the 

 pulley. 



Drawing Taper Keys. A taper key can usually be re- 

 moved by driving the pulley toward the thin end of the key. 

 Often, however, the pulley cannot be driven a sufficient dis- 

 tance to loosen the key because of its coming against a box 

 or another pulley. If the end of the key projects beyond the 

 hub, it may be removed by catching it with a pair of horse- 

 shoe pinchers and prying with them against the hub, at the 

 same time hitting the hub with a hammer so as to drive pulley 

 on. Sometimes the end of a key may be caught with a claw 

 hammer and loosened by driving on the hub of pulley as 

 explained. If a pulley is against the box and key cut off flush 

 with the hub, it may be necessary to remove the shaft, drive 

 the pulley on until the key loosens or if key-seat be long 

 enough, a "drift" may be used from the inside. 



Covering Pulleys. The smaller pulleys on which the 

 belts are likely to slip are covered or lagged with leather or 

 other similar material. The important thing in covering 

 any pulley is to get the leather tight, because it will soon 

 come off if there be any slack in it. 



Najled Covers. Some pulleys are cast with recesses in 

 their rims for the insertion of wooden wedges. These pul- 

 leys are easily lagged because the covers are fastened, simply 

 by nailing to the wooden wedges. To re-cover a pulley 

 fitted with wooden wedges, take off what remains of the old 



