A system for harvesting bone graft material for use during bone fusion surgery. In one embodiment, a bone cutting tool has a blade fixed on a distal end of a shaft. The distal end of the shaft is pivoted on a cage set between two bones to be fused, and the blade is activated to cut into the bones and form a solid bone segment in each bone as the tool shaft turns. A paddle is arranged to be inserted between the bones, and to displace the cut bone segments so that a leading portion of each segment enters the bone opposite the bone from which the segment was cut, a central portion of the segment spans across the bones, and a trailing portion of the segment remains in the bone from which it was cut. The displaced segments act as strut grafts to fuse the bones to one another.