Provided is a Bone Cutting Guide (BCG) for facilitating the cutting of a patent's bones that may include an outer shell, comprising an upper shell; and a lower shell; a left guidance sphere, comprising a first plurality of pin guidance holes; and a first guide surface; a right guidance sphere, comprising a second plurality of pin guidance holes; and a second guide surface, wherein the left and right guidance spheres are positioned between the upper and lower shells; and a plurality of fasteners configured to hold the upper and lower shells together and, when tightened, secure the left guidance sphere and right guidance sphere into selected positions.