Spiral Grooving In order to reduce differential pressure sticking, the surface of drill collars can be spiral-grooved.note 1-Loss of weight is approximatively 4%, compared to slick drill collars. note 2-Length of spiraled section allows reconditionning of connections.

Stress Relief Groove & Bore Back Box

Stress relief grooves improve bending strength of pin and box connections and, therefore, durability. Stress relief grooves for box and pin are defined by API. Bore back box is a gradual reduction of internal diameter by gradually increasing material cross sectional area at critical section. This will ultimately drastically reduce stress concentration during static / dynamic loading and prevents box connections from failure.

Hardbanding

We provide several hardbanding materials for customer’s choice: Arnco-100xT, Arnco-300xT, TCS-8000; Smooth surface free of tool marks increases flexibility and permits bending without cracking. API Stress-Relief Groove pin Last scratch of box thread covered by pin API Bore Back Box Large radii reduce stress concentrations .

Slip and Elevator Recess

Slip and elevator recesses improve downhole handling efficiency and safety. Slip and elevator recesses are machined in accordance with API 7-1.

Recommended Hardbanding Location

-Drill collars with slip and elevator recesses (ZIP) 4” long wear pad above elevator recess 1” long wear pad above slip recess. 10” long wear pad under slip recess

-Drill collars with slip recess: 10” long wear pad under slip recess, 4” long wear pad above slip recess.

-Drill collars without slip and elevator recesses: 10” long wear pad at 30” from pin shoulder.