Selecting a Cable Tool Bit:
Supreme: Our most commonly used all-around bit. The Supreme hard rock bit with its full gauge and flat face can handle almost any formation from granite and basalt to limestone, hard sandstone, dolomite or most any other formation you may encounter while drilling.
Drop Center: Designed for unconsolidated formations, the Drop Center features a full gauge and concave face. The concave face allows cuttings to escape faster providing a higher unit load on impact and helps keep the bit centered for a straighter hole. Use on granite and basalt to limestone, hard sandstone, dolomite and hard pan mixed with hard rock.
Soft Rock: For aggressive soft rock drilling. The Soft Rock features a concave face and extra channels to blast away shale, slate, clay, sandstone and medium limestone. The larger channels reduce the need for re-drilling of settled material.
“Z”: Named for the appearance of the face, the Z bits are designed for gravel and sandy rock formations. The leading edge creates a “scooping” action while the reduced shoulder area allows gravel to fall easily past the bit reducing the possibility of being wedged against the casing. Carbide inserts fracture any hard rock encountered in these types of formations.
Eccentric: The head of these bits are offset from the centerline ½” allowing the bit to overdrill approx. 1” in one full rotation. This design allows the bit to fit through a standard sized casing while drilling an oversized hole. Eccentric bits can be very effective when setting casing into rock or through boulders.