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APPLIED SCIENCE 



Circular Pitch. The circular pitch of a gear is the distance 

 measured along the pitch circle from the center line of one 

 tooth to the center line of the next. 



FIG. 155. 



Diametral Pitch. The diametral pitch of a gear is the 

 number of teeth per inch of pitch diameter. (For example, 

 if a gear has 30 teeth and its pitch diameter is 3 in., the 

 diametral pitch is 30 * 3 or 10.) 



Addendum. The addendum of a gear is the height of the 

 top part of the tooth, i.e., the distance from the pitch line to 

 the point of the tooth. 



Dedendum. The dedendum of a gear is the working depth 

 of the tooth below the pitch line. It is always equal to the 

 addendum. 



Working Depth. The working depth of the teeth of a 

 following gear is the depth to which the teeth in the mesh- 

 ing gear center into the spaces between the teeth of the first 

 or driving gear. 



Clearance. The clearance of a gear is the amount that the 



