Curved framework with dowels.
This is a more legitimate use for dowels than shown at B in that the tenons of the curved rail would have short grain. Note that extra thick stiles are needed to enable the curvature to be continued right across.
Dowels are used to strengthen the butt joint. The square cramping lugs are cut away after assembling. Applied pieces: These are sometimes needed for such items as shaped feet. Note that one block may have to be wider than the other depending upon the particular application.
In all cases the dowels should be grooved along the length otherwise the wood may be split open by the imprisoned glue when the dowels are knocked in.
Lapped and tongued-and-grooved joints.
Used for joining the corners of light work. It shows only a narrow strip of end grain, but nails are needed to hold the parts together as well as glue.
Double lapped joint. That is a variation of that at A and possibly rather stronger, both parts being rebated. Nails are needed and these should be driven from the side into the top. Nails entered downwards would have little grip in the thin lap at the top.
- A glued or butted joint strengthened with dowels;
- B dowelled framework joint;
- C dowels used for shaped framework;
- D shaped frame jointed with dowels (note cramping lugs);
Double lapped joint.
That is a further variation of A. In this case holding nails should be driven downwards through the top into the rebate at the side.
Bare-faced tongued-and-grooved joint.
They have the advantage that nails need not be used, but are suitable for light work only owing to the short grain to the side of the groove, D. That at E is similar to D but is rather more satis-factory in that the upright is set in from the edge so that there is greater width of wood to the side of the groove, and less liability for it to crumble. Sometimes the joint at F is used to join thin wood to thicker as, say, in the case of a drawer shelf with normal rail at the front and thinner wood to the rear.
Lapped and grooved joints. Those are variations of the above. They are not specially strong, and H is suitable for machine work only.
Mechanical joints, Rule joint.
That is used for flap tables at the hinging edge. Special hinges, countersunk upon the reverse side so that the knuckle projects into the thickness of the wood, are used. One flap is wider than the other so that it bridges across the gap formed by the hollow of the flap. Set gauge to hinge center and mark ends of main top. Decide thickness of top fillet and gauge in at ends of main top, and on joint edges of top and leaf, gauging from bottom. Distance between two gauge lines gives size. Set gauge to this and mark ends, top, and bottom of main top, and bottom of leaf. Intersection gives hinge center.
That illustrated is a simple alternative to the knuckle joint, C. The whole thing can be cut with saw and straight chisel cuts. The bottoms of the notches are cut at 45 degrees enabling the square corners of the moving parts to clear.