X / XN Lock

Locking Mandrel
 
The "X" Locking Mandrel operates in the same way as the "R' Locking Mandrel. The "X" Locking Mandrel is used in standard weight tubing instead of heavy weight tubing the "R" Locking Mandrel is used in. The "XN" Locking Mandrel is the "no go" version of the usually selective locks. The keys have an angled shoulder on them instead of the square shoulder of the selective locks. A "no go" shoulder of an equalizing sub or a crossover sub made up the the bottom of the lock must make contact with a bore restriction in the "no go" nipple in order to lock this mandrel in the appropriate nipple. This locking mandrel can be used in conjunction with pump through plugs, positive plugs, safety valves, bottom hole chokes, and standing valves.