Kelly bar is the key element of the rotary drilling rig that transfers the torque and the pull-down from the rig to the drilling tool. The kelly bar comprises of high strength but ductile telescoping steel tubes with special guide strips, drive strips, pull-down keys and locking elements welded onto the steel tubes.

The gearbox of the drilling rig engages the drive strips and the pull-down keys of the outermost tube to apply the torque and the pull-down respectively to the kelly bar while the locking element on the inside of any given tube engages the drive strips and pull-down keys of the next inner tube to transfer to the inner tube the same torque and pull-down. This transfer of torque and pull-down proceeds from the outermost tube to the innermost one which has a square drive stub at its lower end that connects to the drilling tool.

HEMCO manufactures kelly bars to world class standards using the best quality high strength seamless steel pipes from European steel mills and weld-on elements made from special heat treated steels.
Parameters

Kelly bars for other rigs can be supplied on request.