America United Petroleum

Stress Relief Features

Stress relief features are recommended for drill collars as well as all downhole drilling tools where cyclic fatigue may occur from bending. The API relief groove on the pin and the boreback on the box remove unengaged threads in highly stressed areas of the drill collar connection.

This provides a more flexible connection less likely to crack in fatigue because bending in the connection occurs in areas with smooth surfaces free of stress concentration.