... .9mm,73mm Drill wells for the 88.9mm diameter, threaded at both ends, you need to use the tool joint connection with ... 35CrMo material with material of the tool joint. Our factory has the largest drill in northern China, joint production line, has been certified by ... a number of CNC lathes, special testing equipment, manufacture of drill pipe to meet the geological, geothermal, wells, oil drilling and ...