Abstract: An apparatus for abrading a curved surface includes a rotary wheel provided with a plurality of pins and a corresponding number of flexible members, wherein an endless sandpaper band is slidably wound about each pair of corresponding pins and flexible members. As the wheel rotates, the sandpaper bands abrade the workpiece in such a manner that each sandpaper band slides about its supporting pin and flexible member, thus presenting an ever-changing abrading surface to the workpiece. In a second embodiment, a plurality of rotary shafts are substituted for the pins, and driven through the same driving source as drives the rotary wheel so that a positive rotation is provided the sandpaper bands during the abrading process.

Abstract: A disc-shaped rotary file, having a relatively flat operating surface with a curved outer periphery, is formed of ferromagnetic material and includes a plurality of cutting members. The rotary file also includes a second side opposite the operating surface and a number of stop members protruding therefrom. A complementary support member having a relatively flat surface and curved outer periphery is adapted to receive the rotary file superimposed thereon and includes one or more magnets to hold the rotary file in place. The support member also defines one or more depressions or slots for receiving the protruding stop members for preventing the rotation of the rotary file with respect to the support member and for rotation of the file when the support member is rotated.