Patent ID: 8109699

Claim:
A boring bit having a head having a bottom; a top; a mounting recess formed on the head near the top and having a bottom; a vertical restricting surface formed on the bottom of the mounting recess and having a center; and a threaded hole formed through the center of the vertical restricting surface; and two holding protrusions formed on and protruding from the vertical restricting surface of the mounting recess beside the threaded hole and each holding protrusion having an upper edge; a lower edge; and two oblique restricting faces respectively and aslant formed on the upper edge and the lower edge of the holding protrusion; a blade assembly detachably attached to the head and having a bottom; a top; a mounting base formed on the bottom of the blade assembly, detachably mounted in the mounting recess of the head and having an inner surface being a flat surface, mounted in the mounting recess of the head and abutting with the vertical restricting surface of the mounting recess; a through hole formed through the mounting base and aligning with the threaded hole of the mounting recess; and a guiding channel laterally formed in the inner surface of the mounting base, communicating with the through hole of the mounting base and mounted around the holding protrusions of the head and having a top inner side; a bottom inner side; and two abutting surfaces respectively and aslant formed on the inner sides of the guiding channel and respectively abutting with the oblique restricting faces of the holding protrusions; and a fastener mounted in the through hole of the mounting base and screwed with the threaded hole of the mounting recess to connect the blade assembly with the head; and a blade detachably mounted on the top of the blade assembly.