An atherectomy burr having an operating diameter that is larger than the diameter of a catheter in which the burr is routed. The burr may include a flexible polymeric tube that is plated with an abrasive and that expands when the burr is rotated. Metal fibers are embedded into burr to improve strength and to control the maximum expansion diameter of the burr. The abrasive is plated on the burr by first selectively exposing the underlying metal. The exposed metal is then plated with a layer of metal such as nickel having a slurry of diamond particles disposed therein using an electro and/or electroless plating method. When the burr is rotated, the polymeric tube expands by centrifugal force to ablate a new lumen in the patient's vessel.