Patent ID: 7896590

Claim:
A drill machine comprising: a housing; a motor coupled to said housing; an arbor defining a bore and coupled to said motor for rotation with said motor; a driving device mounted to said arbor and extending into said bore; and a cutter extending along a central axis and including a shank portion and a cutting portion each extending along said central axis; said shank portion extending along said central axis between a first end and a second end with said cutting portion extending from said first end and with said shank portion terminating at said second end; said shank portion defining a retaining recess and a pair of flats with one of said flats extending in a first plane and the other of said flats extending in a second plane perpendicular to said first plane and with said driving device engaging one of said retaining recess and said pair of flats; wherein said retaining recess is further defined as an entry channel extending from said second end for guiding said driving device during insertion of said shank portion into said arbor and a retaining channel extending from said entry channel for selectively retaining said driving device; and wherein each of said entry and retaining channels have a trough portion extending toward said central axis with said trough portions of each of said entry and retaining channels having a common configuration for slideably receiving said driving device.