Big Hole Drilling Tools offers a large selection of hole opener cutters for our extensive selection of hole openers. Milled tooth and Tungsten Carbide Insert (TCI) sealed bearing cutters are available for Security Type hole openers. Milled Tooth sealed bearing cutters are available for Varel Type hole openers. Split-bit hole openers are constructed from the bit thirds of tri-cone bits and can be manufactured to fill a variety of applications.