Torque necessary to raise cnx in threaded coupler

[rpb2005]

I have rods in a vertical configuration that are joined by a threaded coupler. What is the force necessary to adjust the OAL of the rod configuration through turning the coupler

 

[diamondjim]

RPB,
You need to supply a lot more information
like size, number of threads per inch,
load on coupler, are these right and left
hand threads?