DRILL COLLARS are made from 4140/4145 seamless chromemoly alloy trepanned solid bar stock or from seamless mechanical tubing. To ensure optimum strength and ductility, each bar is heat treated to a Brinell Hardness Range of 285/341. Additionally, all bars are impact tested to 40 ft. lbs. Izod Z minimum to ensure hardness at least 1" below the surface.
Each bar is machine straightened to within 1/8" in any 5' length and to 3/16" in total axial length. All threads are precision inspected for manufacturing accuracy. These tests and others ensure that all Hacker Drill Collars meet or exceed API specifications.
Standard Sizes, Bores, and Connections for Drill Collars (API Spec 7)
Optional feature include cold rolled thread roots, modified bore back boxes and API stress relief grooved pins, and slip and elevator recesses. Mill chemical and physical certification with each order upon customer request.
1. Low torque face.
2. Ratio of box to pin section modulus See API Spec RP 7G for Explanation.
3. 30-foot length drill collar
All dimensions in inches, unless otherwise specified.