Abstract: A deburring tool capable of removing burrs and placing chamfers on circumferential edges surrounding both front and back side openings of a borehole, wherein the tool includes an elongated cylindrical arbor, a resilient arm section, and a replaceable cutting insert. In use, the rotating deburring tool is steadily advanced in a forward axial direction until the replaceable cutting insert encounters the circumferential edge of a front side opening, whereby the tool removes any burrs and creates a chamfer on that opening. Continued forward axial movement causes the replaceable cutting insert to retract within the arbor such that the tool continues through the borehole without damaging its interior surface. As the tool emerges from the back side opening of the borehole, the replaceable cutting insert is again allowed to extend out of the arbor and into a deburring position.