Stringed instrument
BACKGROUND OF THE INVENTION 
     This invention relates to stringer instruments and more particularly such instruments in which the strings are positioned over a fretboard such as a guitar, banjo, and the like. Efforts to improve the fingering action, playability, and construction are many by prior luthiers. Prior construction methods have been a fretboard cemented to a separate neck or a fretboard carved into the neck. This process of construction prohibits rapid interehangability for purposes of repair or ascetic considerations. 
     An earlier arrangement is shown in the U.S. patent of Muncy, U.S. Pat. No. 3,787,600 of 1974, in which the fingerboard was carved into the neck. 
     Other undulated fingerboards have been made in the past, as shown in U.S patent of Muncy, U.S. Pat. No. 3,787,600 of 1974, with a plane transverse line form undulated with flush frets at the bottom of the groove. 
     Conventional fretting, shown in U.S. patent of Veres, U.S. Pat. No. 3,481,238 of 1969. showing traditional raised fret form, using tang anchoring, and adhesive fastened fingerboard. 
     SUMMARY OF THE INVENTION 
     The present invention overcomes the deficiencies of the arrangements described above in that it provides modular construction by using a dovetailed form to fasten the fingerboard to the neck to allow ease of replacement and ascetic considerations. In the preferred embodiment a dovetail form on the fingerboard, provides a slide in slide out feature for rapid replacement of a worn or damaged fingerboard, while also allowing various wood or other materials selection for grain and color. 
     I have found that continuous undulating are facets from the high points at the frets to the depressed regions between the frets allows the bending of the strings in either direction to produce vibrato of a note or chord, and allows significantly improved slide noting and slide chording playability. In the preferred embodiment, the fret form is machined into the fingerboard in a manner as to allow a geometric base form to lock the fret in place for added stability. 
     The object of my invention is to provide a fretboard for a stringed instrument which has modularity of construction for ease of replacement and ascetic considerations. 
     It is an object of my invention to enhance the stability of the fret in the fretboard. 
     It is an object of my invention to provide undulating arc facets from high points at the frets to depressed regions between the frets. 
     An important object of my invention is a provision of a fretboard as outlined above, in which the apex land area is in the form of an arc. 
     These and other objects and advantages of the invention will become apparent from the following description, the accompanying drawings, and the appended claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a plan view of a guitar embodying my invention; 
     FIG. 2 is an enlarged longitudinal fragmentary section taken through the neck; 
     FIG. 3 is an enlarged fragmentary section of a portion of the neck and string; 
     FIG. 4 is an enlarged end view cross-section showing the are and the dovetail of the fingerboard taken generally along the line 5--5 of FIG. 1; 
     FIG. 5 is and enlarged end view cross-section showing the dovetail in the neck taken generally along the line 5--5 of FIG. 1; 
     FIG. 6 is an isometric view showing an are facet area and the are land area of the fret taken generally along the line 5--5 of FIG. 1. 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENT 
     A guitar having a neck made according to the present invention as illustrated in FIG. 1 is included in the conventional body or base 10, head 14 and in FIG. 5 neck 12. While the invention is shown as being applied to a guitar, it is understood that the same may be applied to any stringed instruments incorporating a neck where spaced frets are, or could be, incorporated; such as a violin. 
     The guitar includes conventional strings 15, illustrated in FIGS. 2, 4, which extend between the bridge 16 and the nut 17 in overlying relation to the fret board portion 20 of the neck 12. The fret board 20 is formed with a dovetail shape 18 assembled with neck 12 with conforming dovetail 18. Either neck 12 or fret board 20 can be utilized with male or female dovetail 18. 
     While I have shown the modular feature of assembly with dovetailed form, it is within the scope of my invention to utilize other forms of geometric forms of assembly, such as tongue and grooved. 
     The fret 30 is formed geometrically to a T shape as illustrated in FIG. 2. The fret 30 is installed into a matching T-slot 33 cut into the arc land region (FIG. 6) 11 of the fretboard 20 on a corresponding arc. 
     The fret board 20 is provided with a plurality of transversely extending, longitudinally spaced imbedded frets 30. The frets 30 have playing surfaces which conform to the apex arc land regions 11. 
     The playing surface of the board 20 is formed with a slight periodic transversely-oriented facets (FIG. 6) 13 which undulates, and is formed on an arc that rise at high points defined as the arc land region 11 of the fret and low points substantially midway between the frets. Preferably the entire playing surface is undulated in this manner, forming an obtuse angle in the playing surface with the apex arc land 11 of the frets. The included angle may be on the order of 170-188 degrees with the result that a slightly depressed region 35 (FIG. 2, 3, 6) is formed between a pair of frets 30. This results in a small portion of the arc facet 13 behind each fret 30 sloping uniformly away from the string 15. The arc, which the facet is formed on, may be on the order of 12&#34; radius but not limited to a 12&#34; radius, and may also be in compound radii configuration. 
     While the form of apparatus herein described constitutes a preferred embodiment of the invention, is to be understood that the invention is not limited to this precise form of apparatus, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.