The dimensions of imperial stud bolts are defined in the ASME B16.5 Norm, whereas ISO 1891 defined the dimensions and measures of metric stud bolts.

In any case, the theoretical length of a stud bolt can be calculated with the following formula :

L = 2 x (S + he + eb + i) + J


  • S: free threads (1 to 2 pitch)
  • he: nut thickness
  • eb: flange thickness (with tolerance)
  • i: height of raised face (for 150 and 300 flanges rating, the height of raised face is included in eb height)
  • J: gasket thickness
Bolt sets lenght calculation

(Source Trouvay & Cauvin - Piping equipment "Blue book")




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