Thread Crest Definition
- The crest is a flat (or rounded) surface connecting the flanks at the top of the thread grooves, whether internal or external.
- The crest width depends on the amount of truncation applied to the fundamental triangle, which is defined by the specific thread standard.
Internal Thread
- Crest width of 60° standard threads: Fcn=0.25 X P
- The minor diameter is measured on the crest.
External Thread
- Crest Width of 60° standard threads: frc=0.125 X P
- The major diameter is measured on the crest.
