2. To unscrew stuck pipe in a well. This is done by locating the free point. A left-handed torque is then placed on the assembly, and a string shot is used to break and remove the free section. The stuck pipe then can be pulled with a fishing operation using a washover tool. in a blind back-off, the loints are all tightened with right-handed torque under tension or overpull. Slow left-handed torque applied by the pipe tongs with the swivel disconnected is then applied with overpull. After one turn, the overpull is increased and the assembly should unscrew near the free point. If the stuck pipe cannot be fished, the well is plugged back and sidetracked.
3. To raise the drill bit a short distance off the bottom of the hole.
4. To slack off on a line.
5. To let drilling line out of the drawworks.