... specification and SY/5146 standard. 1.Size: 3 1/2", 4",4 1/2", 5", 5 1/2",6 5/8"2.Products ... replacing part of the drill collars. The advantages include:1.Reduced torque in high-rpm, deep drilling.2. ... compared to handling a long string of drill collars.3.Fewer tool-joint connection failures.4.Easy in ... particle, and Arnco 100XT.HWDP could be coated internally with DPC (equivalent to TK 34) as customer's ...