Frames and supports in 15th and 16th-century Southern Netherlandish painting

CHAPTER II 54 Fig. 19 (continued). 19. Variant of 18, with the back tenon shoulder cut at an angle (rare). 20-21. Variants of joint no. 19, with the mitres on the rail and the stile meeting at an acute angle (20) or an obtuse angle (21), (rare). 22. Typical slotted joint for lower corners, where there is an inclined sill on the rail. As in the mortised version (10), the tenon is on the stile, with one tenon shoulder angled to the incline of the sill. Lap joints . 23. Lap joint, cut square. 24. Variant, with mixed cut.