(E) Tungsten Carbide Coated Cones (E) Tungsten Carbide Coated Cones All exposed portions of the cones are coated to provide resistance to cone shell erosion which limits bit life. (G) Cone Back Row Insert (G) Cone Back Row Insert Steel tooth bit option only adding a gauge row insert to the design enhancing gauge holding ability of the bit. (H) Steel Center Air Jet Nozzle (> 7 7/8” only) (H) Steel Center Air Jet Nozzle (> 7 7/8” only) A-Force type bits offer a center air jet nozzle featuring three additional ports for better cutting structure and hole bottom cleaning. (J) Center Jet Nozzle (> 7 7/8” only) (J) Center Jet Nozzle (> 7 7/8” only) A fourth interchangeable jet nozzle is installed in the center of the bit to reduce bit balling or provide extra flow. (K) Skirted Shirttail (K) Skirted Shirttail Skirting is an option for reverse circulation applications. A triangular piece of steel is added between the bit legs to help push fluid to the bottom of the bore hole for easier cuttings removal through the center of the bit. (M) Shirttail Hardfacing (M) Shirttail Hardfacing A generous application of tungsten carbide hard facing is applied to the shirttail lower and leading edges to provide seal protection. (P) EdgeGuard (P) EdgeGuard Patented tungsten carbide micro shields are brazed into shallow receptacles to provide the ultimate in shirttail tip protection. (R) Stabilization Inserts (R) Stabilization Inserts Provide bit stabilization and additional protection to the pressure compensator in deviated well bores. (S) Leading Edge Shirttail Inserts (S) Leading Edge Shirttail Inserts TCI’s are placed along the leading edge of the shirttail providing wear resistance in high RPM applications. (V) V-Jet Hydraulics ( Std. on IADC 537 and softer) (V) V-Jet Hydraulics ( Std. on IADC 537 and softer) The V-Jet aimed flow stream produces better cone cleaning, improving bit penetration rates. (Z) Diamond Enhanced Shirttail (Z) Diamond Enhanced Shirttail A premium shirttail protection package with PCD inserts strategically located to provide maximum shirttail protection. Diamond Feature Diamond Feature The use of PCD inserts in the cones of a bit add cutting structure abrasion resistance. Several options of where and how much PCD should be used are represented. Back row – PCD inserts in the back row increase a bits ability to hold gauge in abrasive applications. (D) 33% Back row PCD inserts (D1) 50% Back row PCD inserts (D2) 66% Back row PCD inserts (D3) 100% Back row PCD inserts Back row and Gauge – PCD inserts in the back row and gauge of a bit provide the best wear resistance in the harshest abrasive environments. (DD) 33% Back row and 100% gauge (D1D) 50% Back row and 100% gauge (D2D) 66% Back row and 100% gauge (D3D) 100% Back row and 100% gauge (D3DD) Full PCD cutting structure For specifications, application solutions, and Features availability please contact your local Varel Oil & Gas representative.