4.6.2.1 Frontal Parallel Joints
Frontal parallel joints are used to increase the length of beam elements. They are commonly used in the production of upholstery frames, strips of furniture boards, door rails and in joinery. This group of joints include bevelled lap joints, straight lap joints, slant lap joints, wedge joints, straight bridle joints, slant bridle joints, multi-wedge (finger) joints (Fig. 4.30).
4.6.2.2 Longitudinal Parallel Joints
Longitudinal parallel joints are used to increase the thickness, width or thickness and width of beam elements (Fig. 4.31). Usually, they are used in the production of upholstery frames, strips of furniture boards, door rails, joinery, as well as large-size building elements (beams, girts, trusses, girders, etc.). They are often used in conjunction with frontal parallel joints. This group of joints includes spline rectangular, spline trapezoidal, spline triangular, spline semicircular, spline rectangular with a ledge and spline framed (Fig. 4.32).