... , Non magnetic drilcollars, Short drill collars, Drill tool stabilizers, Non magnetic drill tool stabilizers, Integral heavy weight drill pipes, etc.♦ ... API Spec 7-1 or SY/T5051-91Standard.5. Inspection&Test: When producing, traceability are maintained from the receipt of ... each workpiece body. During each manufacturing process, inspection and test are performed.6. Specification: Bit Size(in)Working OD ...