TIMBERLINE by Amana 320-26 TIMBERLINE CORNER ROUND 3/8 Radius D2 Flute with Ball Bearing GuideThe corner-rounding bit rounds an edge to a given radius. The tool is shouldered to cut a fillet. The cut can be used to ease edges, as a simple profile, or as a part of a complex one. Also known as roundover, rounding over, and quarter-round.