Abstract: Provided is a tool for polishing the surface of frets, a fretboard or a fingerboard of a stringed instrument, so as to shape and adjust the frets, the fretboard or the fingerboard to have a curve appropriate for the stringed instrument having a curve.

Abstract: A file having concave portion is most well-known. The use of this file has a risk of ruining an effect of a leveling of frets due to undesirable scrape of a top portion of the fret and to losing a normal function of the fret due to a change of the height thereof. Since the file is held by hand, a tool angle varies in use. Since the size of a polishing surface of the tool is not suitable for all types of frets, a complete set including a various size of the files is required in order to select and use one of them as necessary and appropriately. Therefore, a tool of the invention has been made to solve these problems as follows: 1. the top portion of the fret is not scraped and the resultant fret after the leveling thereof are protected as important; 2. since the tool is placed on the fretboard with two side portions of the tool, and thus the tool angle is kept constant (thus, during use the axis of the tool is not rotated and the centerline of the tool is not displaced); 3.

Abstract: Provided is a tool for simultaneously correcting a radius of curvature of frets, a fretboard or a fingerboard of a stringed instrument and leveling the frets while strings are on the stringed instrument. In order to introduce the strings of the stringed instrument inside the tool, the tool includes grooves, provided at the bottom of the tool, and spaces leading from the grooves, provided inside the tool. The tool is moved back and forth, in a condition where the bottom of the tool contacts the polishing object, while the strings are on the stringed instrument.

Abstract: A file having concave portion is most well-known. The use of this file has a risk of mining an effect of a leveling of frets due to undesirable scrape of a top portion of the fret and to losing a normal function of the fret due to a change of the height thereof. Since the file is held by hand, a tool angle varies in use. Since the size of a polishing surface of the tool is not suitable for all types of frets, a complete set including a various size of the files is required in order to select and use one of them as necessary and appropriately. Therefore, a tool of the invention has been made to solve these problems as follows: 1. the top portion of the fret is not scraped and the resultant fret after the leveling thereof are protected as important: 2. since the tool is placed on the fretboard with two side portions of the tool, and thus the tool angle is kept constant (thus, during use the axis of the tool is not rotated and the centerline of the tool is not displaced): 3.

Abstract: Provided is a tool for polishing the surface of frets, a fretboard or a fingerboard of a stringed instrument, so as to shape and adjust the frets, the fretboard or the fingerboard to have a curve appropriate for the stringed instrument having a curve.

Abstract: Provided is a tool for simultaneously correcting a radius of curvature of frets, a fretboard or a fingerboard of a stringed instrument and leveling the frets while strings are on the stringed instrument. In order to introduce the strings of the stringed instrument inside the tool, the tool includes grooves, provided at the bottom of the tool, and spaces leading from the grooves, provided inside the tool. The tool is moved back and forth, in a condition where the bottom of the tool contacts the polishing object, while the strings are on the stringed instrument.