... .delivery on time Type6"(152mm), 6 1/2"(165mm), 8 1/2"(215.9mm), 9 1/2"(241.3mm), 12 1/4"(311mm) , 13 5/8"(346mm) , ... diameters and high projection. This cutting structure design, combined with maximum cone offset, results in high bit penetration rates. The deep intermesh ... inner rows. This design provides a fast drilling rate and added cutting structure durability in medium to medium hard formations ...