100 The Cultivation and Preparation of Coffee 



Example Problem 4 for toothed wheels. 



Number of teeth of ' ' driver ' ' wheel . 80 

 Number of teeth of * ' driven ' ' wheel . 40 

 Number of revolutions of "driven" wheel 200 

 Find number of revolutions of " driver " wheel. 



40 x 200 = 8000 * 80 = 100, revolutions 

 of " driver " wheel. 



Method of calculating the horse-power that 

 turned shafting is capable of transmitting. 



To know the maximum capacity of horse- 

 power of a turned steel shaft within the limit 

 in which it is capable of doing properly its duty, 

 multiply the cube of the diameter of the shaft 

 by the number of revolutions per minute and 

 divide the product by the co-efficient 80. 



Example. What horse-power could a 3-in. 

 shaft transmit running at 100 revolutions per 

 minute ? 



Method. The cube of 3 is 27. 

 27 x 100 = 2700 * 80 = 33-75 horse- 

 power. 



The following table shows the horse-power 

 that can transmit shafts of various diameters 

 running at speeds of from 50 to 250 revolu- 

 tions per minute. The power that same 



