Equivalent Normal TPI
of Diametral Pitch Knurls
All Diametral Pitch Knurls Made to American Standards (ASA B5.30 1984).
Diametral Pitch Knurls produce the D.P. number of teeth per inch of diameter.
Rolled Circular Pitch Knurls, produce the TPI number of teeth per inch of 
circumference measured normal to the teeth.
DP Equivalent Normal Circular TPI
  Straight Teeth 30 Diagonal
64 20.7   23.9  
96 30.8   35.6  
128 41.1   47.4  
160 51.2   59.1