FARM MOTORS 



321 



than 4000 feet per minute, and 2000 feet is a more common 

 velocity. 



Leather Belting. Leather is the standard material for 

 belting and is considered the most durable, when protected 

 from heat and moisture. A good leather belt should last 

 from ten to fifteen years when used continuously. It is 

 customary to run the belt with the grain or smooth side next 

 to the pulley, as the strength of the leather is largely centered 

 in this side of the belt; if run with the smooth side out it is 

 quite likely to become cracked. 



In order that leather belts should render good service they 

 should be properly cared for. 

 As a belt bends, the fibers of 

 the leather slip over one an- 

 other, and for this reason beRs 

 should be oiled or lubricated. 

 Neatsfoot oil is the standard 

 oil for this purpose. There are 

 many good belt dressings on 

 the market, but there are oth- 

 ers which are decidedly inju- 

 rious. A leather belt works best 

 when pliable enough to adhere closely to the pulley, and 

 rosin and other such materials are to be avoided. 



Rubber Belting. Rubber belting is made of canvas 

 thoroughly covered with rubber. It is made in thicknesses 

 of two-ply and up, three- and four-ply being common thick- 

 nesses. A rubber belt operates quite satisfactorily under 

 wet conditions. 



Canvas Belting. Canvas belting consists of several thick- 

 nesses of canvas, four- and five-ply belts being the most com- 

 mon. The canvas is thoroughly stitched together and then 

 filled with oil to keep out the moisture, and finally painted. 



Fig. 200. Sample of canvas, rub- 

 ber, and leather belting. 



