Finger joint cutter Commonly used to join two boards of equal width and thickness end to end for long sections of molding or trim. Finger-joints are used to join short pieces of wood together to form units of greater length. The joint is composed of several meshing wedges or “fingers” of wood in two adjacent pieces and is held together with glue. Primed Finger-Joint, also known as a comb joint, is a woodworking joint made by cutting a set of complementary, interlocking profiles in two pieces of wood, which are then glued. The cross-section of the joint resembles the interlocking of fingers between two hands, hence the name "finger joint".