An abrading head for a high-speed rotation atherectomy device is disclosed. The head has its center of mass laterally displaced from the rotational axis of the drive shaft. As the drive shaft spins, centrifugal force forces the abrading head radially outward. At high speeds, and the abrasive portion of the head may subtend an abrading cylinder larger than at low speeds or at rest. The abrading head has two components, each having a different density. The connection portion may be an incomplete cylinder, which fastens onto the drive shaft, and may be a relatively low density metal, such as stainless steel. The eccentric portion may be a relatively high density metal, such as tungsten or tantalum, and is attached to the connection portion. The eccentric portion has all or most of its mass on one side of the rotation axis of the drive shaft, providing a larger separation between the center of mass of the abrading head and the rotational axis of the drive shaft than if the abrading head were made from only one material.
