The Safety Joint is a simple design composed of an upper pin section (1) and a lower box section (2). The upper and lower sections are threaded together by a coarse acme thread profile (3) which is sealed on either end by sets of o-ring seals (4). These seals allow the Safety Joint to easily withstand external and internal pressures and are also used to prevent debris from contaminating the acme threads.
Disengaging the Safety Joint Downhole
A To break the Safety Joint connection, rotate the drill string to the left at 40% of the Safety Joint’s right-hand make up torque; one turn in straight or shallow holes, two to three turns in deep or crooked holes.
B Pick up the drill string until at least 1000 lbs (445 daN) of weight, but not more than 2000 lbs (890 daN) remains on the Safety Joint. If more than 2000 lbs (890 daN) is applied, the Safety Joint will release but there exists a large possibility of causing damage to the threads when the Safety Joint releases.
C Pick the string up slowly while rotating to the left to unscrew the Safety Joint. As the course threads unscrew, they will lift the pipe approximately 1/2 inch (12.7 mm) per revolution.
D Carefully apply 1000 lbs of weight and rotate slowly to the right. An increase in torque will indicate that the Safety Joint has re-engaged.
Re-engaging the Safety Joint Downhole
A Lower the string into the hole until the Pin Section contacts the Box Section.
B Carefully apply 1000 lbs of weight and rotate slowly to the right. An increase in torque will indicate
that the Safety Joint has re-engaged.