Abstract: An arbor for a guided circular saw has three symmetrical lobes. The lobes have end regions with profiles which follow an arc centered on an axis of rotation of the arbor. The lobes have driving regions with profiles which follow the arc of a circle centered in an opposing lobe. A saw for use with the arbor has an eye with a shape which follows the contour of the arbor. The saw is capable of floating axially along the arbor. The saw and arbor can be used to advantage in sawing machines such as edgers. The arbor provides a much larger saw contact area than do prior art arbors. In one embodiment of the invention the saw is mounted between a pair of spaced apart collars on the arbor. The collars guide the saw but are not tightly clamped to the saw.