PALMER: THE DESIGNING OF CONE PULLEYS. 75 
step cones it is not nearly so easy or satisfactory to do so as to use 
the diagram provided for the purpose. 
LENGTH OF BELT. 
According to these special rules for three step cones no attention 
is paid to the length of belt. It may be figured quickly for this 
particular case as follows: 
Multiply the radius of the middle step by 3.1416 and add the 
distance between centers. This gives | the half length of belt. 
CONCLUSION. 
Any case of cone pulley designing will be found to fall directly 
under one or the other of the preceding cases and can be treated 
correctly by following the rules there given, even though the proofs 
are not known. 
The rules can be used with more satisfaction, however, if the 
discussion which has been presented be followed first. With the 
full understanding of the intricacies of the problem and of the steps 
of the discussion leading up to the final conclusion, it will be much 
easier to appreciate the significance of the rules and to use them 
correctly. Hence it is urged that all who have to deal with the 
rules follow first through the full discussion, using, afterward, the 
rules for reference. 
