Core bits are designed to produce holes which provide clearance for pipe of conduit runs through floors and walls. The bits enable a hammer drill or rotary hammer to produce holes which are larger than the tool rating by cutting the circumference of the hole while leaving the center solid. Heavy duty core bits are offered for drilling through concrete, block, brick and soft stone.
Heavy wall core bits are machined from a single piece of forged steel for long life and are designed for use with Spline or SDS-Max rotary hammers. The top or head of the bit is crowned to direct the hammering energy through the outside wall and into the cutting teeth. The carbide cutting tips are made with a slighty negative cutting angle on the face to allow them to be used in the rotary hammering mode. To provide optimum drilling, the carbide tips or teeth are inserted at irregular intervals in the core to minimize vibration and one piece and two piece core bits are offered. One piece bits have a shank which is friction welded to the forged core body provide the most efficient drilling. Two piece bits have rope threads machined to tight tolerances to minimize energy loss at the connection. As with all adapters, there is normally a 10 to 15% loss of hammering energy with a two piece system.