... and bearing life.3.Bearing Structure of this series tricone rock bit :High precision bearing with two thrust faces. ... bearing are improved and suitable for high rotary speed.4.Seal and LubricationThe advanced metal seal package consists ... 617,6379 7/8250.8127,517,537,617,63712 1/4311.1114,126,127,517,537,617,63713 ... 617,63715381124,517,537,617,63715 1/2393.7124,517,537,617,63717 1/2444.5114 117 124 126 ...