Model Number: 8 1/2SJT547G(IADC547) Brand Name: TRANSTONE Key Specifications/Special Features: Cutting structureThe wear-resistance of teeth is enhanced with premium tungsten carbide hard facing on the tooth surfaces for steel tooth bit. The durability of premium tungsten carbide inserts is improved with new formulas and new techniques for insert bit.Gauge structureMultiple gauge protection with gauge trimmers on the heel and gauge inserts on the gauge surface of the cone, tungsten carbide inserts and hard facing on the shirttail increases gauge holding capability and bearing life.Bearing StructureHigh precision journal bearing with two thrust faces. Balls lock the cone. hard-faced head bearing surface. Cone bearing inland with friction-reducing alloy and then silver-plated. Abrasion resistance and seizure resistance of the bearing are improved, and suitable for high rotary speed.Seal and lubricationThe advanced metal seal package consists of two metal seals and two elastic energizers. Compressed energizers ensure good contact being kept on two sealing surfaces of metal rings by elastic. This will improve the reliability and durability of bearing seal. The pressure compensator system and advanced grease can greatly increases the lubricating reliability.Product applicationIt suitable for downhole motor and high speed applications. Size(in) Size(mm) IADC WOB(kN/mm) RPM(r/min) Applicable formation 8 1/2 215.9 547 0.35-1.0 220-60 Soft to medium formations with low compressive strength, such as medium soft shale, medium soft limestone, medium soft sandstone, medium formation with harder and abrasive interbed & more