An apparatus is described for making a circular incision in a surface. The apparatus includes a handle and an elongated blade assembly extending from the handle. The blade assembly includes a rotor. The rotor includes a bar having an elongated axis, with at least one blade extending from the bar. The rotor is adapted to rotate about an axis substantially parallel to the blade, the blade being substantially perpendicular to the elongated axis of the bar. The blade assembly is adapted to extend the blade for making the circular incision and to retract the blade. In the retracted state, the bar is aligned with the blade assembly, preventing direct contact between the blade and the surface. Fig.: 1
