Carbide-tipped auger bits are designed to resist damage when boring through wood that contains hidden nails.
The bit features a solid nose with a carbide insert, which is attached or detached by means of a set screw.
The carbide tip is harder than the steel used for making nails, meaning the user can even drill through nailed boards, like decking, without having to worry about damaging the bit.
If a carbide-tipped bit does wear down from cutting through too many nails, the carbide insert can be removed and replaced by unfastening the locking screw and re-tightening it once the insert has been replaced.
Carbide-tipped bits are often L’Hommedieu pattern, which itself is sturdy and resilient.