| 摘要 |
A drill pipe (1; 12) has a journal (2; 15) formed thereon. Integrally formed stop collars (10, 11; 16, 17) are provided at each end of the journal (2; 15). The arrangement enables rotatable tools (18) to be fitted directly to a journal (2; 15) to reduce friction between the rotatable tool (18) and the journal (2; 15). The journal (2; 15) may be of a substantially greater length than the length of the rotatable tool (18) to facilitate lubrication and cooling. Alternatively removable stop collars (30; 31) are secured adjacent the ends of a journal (28) formed on the drill pipe (25). Methods of forming the journal surface (2; 15) during manufacture of a drill pipe are disclosed. There are also disclosed methods for reconditioning an existing drill pipe (20) to form a journal (21) thereon.
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