Thread Root Definition
- The root is a flat (or rounded) surface connecting the flanks at the bottom of the thread grooves, whether internal or external.
- The root width depends on the amount of tip truncation, which is defined by the specific thread standard.
- Root Width of 60° standard threads: Frn=0.125 X P
- The major diameter is measured on the root.
- Root Width of 60° standard threads: Frs=0.25 X P
- The minor diameter is measured on the root.