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

CHAPTER II 60 The mortise is replaced with a sawn slot. This assembly is weaker than the mortise and tenon because of the absence of a mortise shoulder. On the other hand it is easier to produce because most of the operation can be done with a saw instead of a mortise chisel. 4. Half-lap joint (fig. 19: 23-29; fig. 25) Fig. 25. Half-lap joint. Large inside frame with half-lap joints, abundantly pegged. Frans Francken II (attributed to), Crucifixion and Scenes from the Passion , late 16th/early 17th century (Leuven, MM , no. 14 ). Each of the pieces is cut to half its depth to accommodate the corresponding solid portion of the other piece. This assembly was adopted to make the inside of double frames, as produced for the Franckens in the second half of the 16th century (Leuven, MM , no. 13 ; Leuven, MM , no. 14 ). Exceptionally, we have observed the use of half-lap joints to join the elements of a frame in the case of the wings of the small Triptych of the Virgin and Child with St John and St Jerome by Adriaen Isenbrant (Bruges, GM , no. 17 ). Reinforcing bars at the back of the large 15th century works are frequently lap- joined to the uprights. 5. Key and spline joint (fig. 19: 30-31; fig. 26) Fig. 26. Spline. Monogrammed IF, The Ascent to Calvary (PC, no. 4 ). Key and spline joints use a separate piece of wood. A key, which functions as a sort of loose or slip tenon, was adopted from the early 16th century onwards, especially to join the elements of a large panel, but also to join at their top the two parts of the curved rail of a frame. The earliest splines we have observed date from the second decade of the 17th century, where they were used to assemble the cut-back elements of a previously slot-cut frame (Monogrammed IF, The Ascent to Calvary , PC , no. 4 ).