Patent ID: 10835969

Abstract:
A self-aligning counter bore cutting tool and method detachably attaches to a drill, and is rotatably driven by the drill, so as to cut a counter bore into a subfloor. The cutting tool includes an annular frame that has unique arm slots for retaining a plurality of cutting blades in a fixed position while rotating and cutting. A plurality of fastening blocks work to securely retain the blades in the arm slots. At least one oversized depth restriction frame extends beyond the blades to restrict the blades from cutting the counter bore beyond a predetermined depth. The frame includes a protruding shaft bushing that securely receives a drill chuck from the drill to create a secure, aligned coupling to the drill. The shaft bushing also aligns the blades with a mudsill fastening plate in the subfloor, so as to create a concentric counter bore at the appropriate depth in subfloor.