... Alloy steel Certificated by API&ISO9001:2008 8 1/2" New PDC Bits for Well Drilling Description about sell rock bits,tricone ... from 5-1/8” to 13-1/2”.There are different PDC (polycrystalline diamond compact) grades and shapes applied for rock formations as ... the field of mine, transportation, tunnel and hydroelectric for shelving reticular support.Model114,117,127,437,517,617,637 TypeTricone bits ...