Knuckle joint. Swing legs or swing brackets are pivoted with the knuckle joint in the best work. A metal rod forms the pivot. The center must be set in from the ends by exactly half the thickness of the wood. Mark out circles at top and bottom, work the rounded shape, and mark the knuckles, gauging from the same side in every case. Hold the saw on the waste side so that the parts fit reasonably tightly. Cramp together and bore from each edge.
Rebated fall joint.
The advantage is that the fall is flush with the writing top when opened, and when closed there is no gap at the front. Pivoting bracket is useful for light tables for supporting a flap. Note how the ends are cut askew to give clearance.
Bureau fall joint.
With the joint the problem is to find the position of the fixed writing top in relation to the sloping front. Set out the sloping end either on the wood itself or on paper as shown by the thick line. Decide the depth of the rebate around the fall and draw a line parallel with the slope, giving distance X. Where this line cuts the vertical front gives the position of the top of the fixed writing top.
Joints for man-made materials
Further mechanical joints are needed to conceal the layers of the material, enabling moldings, rebates and the like to be worked, or for thickening. A is the simplest form; it shows on both surfaces but for some work this may not matter. If veneered afterwards it would not show at all. Should the appearance of the kipping on one surface be an objection, the feathered type at B can be used.
A stronger form of kipping is that at C. When fixed before veneering it is concealed by the veneer; if afterwards it protects the edge of the veneer. That at D serves both purposes; E is a simple raised lipping; F has double tongues for thick wood and G has a tongued and molded edging. H has a loose tongue. I, J, K, and L are variations. That at J has the advantage of being simpler to work by hand methods. For work to be thicknesses as well as edged M is suitable. N shows the application to a fielded panel.
Details of edgings used for man-made boards.
- simple butted edging;
- tapered form;
- tongued edging;
- rounded and tongued type;
- double tongued;
- molded and tongued;
- loose tongued;
- double chambered and tongued;
- molded and tongued;
- molded and loose tongued;
- rebated and tongued;
- fielded panel; 0 tongue on plywood;
- weakness of tongue on cross-grain of lamina board;
- satisfactory tongue on lamina board;
- useless tongue on chipboard;
- satisfactory tongued edging on chipboard;
- loose-tongued edging for chipboard;
- weakness of edge veneered after surface veneering;
- better treatment of edge veneered before surface veneering;
- tongued edging applied before veneering;
- tongued edging applied after veneering:
- lamina board rebated to receive edging.