Abstract: A novel holder for work pieces, particularly for holding picture frame pieces in which the adjoining mitered ends of the frame pieces are brought together. The inventive concept resides in providing a mechanism which permits primary adjustment of the jaws in such manner that the pieces are easy to insert and wherein as the last increment of movement of the jaws they tightly clamp the pieces and move them endwise toward each other in perfect alignment and after nailing; the mechanism also quickly releases the joined frame pieces because of the electrical toggle linkage employed.