This section is from the book "Modern Buildings, Their Planning, Construction And Equipment Vol2", by G. A. T. Middleton. Also available from Amazon: Modern Buildings.
In making joints with long boards the method of procedure is as follows: - The edges having been shot true and out of winding and ploughed, one board is fixed in the screw, and the tongues fitted. These should fit easily but not loosely, and a bradawl driven in at each end, or a small stop nailed on the end of the groove, to prevent their being driven out when rubbing the joint. If bradawls are used they are then withdrawn sufficiently to release the tongues, which are removed and the groove nearly filled with glue, a glue spoon being used in preference to a brush. The tongues are then replaced and tapped in with a mallet, and the other board held in the position shown in Fig. 88. Both edges are then well glued with a brush, and the loose board turned over and placed in position. It is then gripped by the end, and with the aid of an assistant at the other end it is pressed firmly down and rubbed backward and forward in long strokes until the glue begins to stiffen and "drag." It is then brought to its proper position, the cleats put on and wedged and laid aside in an upright position to dry.
The list of joints used in joinery, of which several are shown in Fig. 89, is an extensive one, and a combination of practical experience and theory enables the skilled mechanic to supply from his repertory a joint to meet the exigencies of every case. The simplest form of groove and tongue joint has been already shown. For wide edges double tongues are used, as shown at No. 1 in Fig. 89. Tongues should always be either "Feather" or "Cross."
All joints are designed to effect the rigid securing together of two pieces meeting at some angle, the right angle being the simplest. The following are some of the joints employed:-
No. 2 is a Square Joint, and must be nailed.
No. 3 is a Plain Mitre and also requires nailing, or it may be secured by one of two methods, one being known as a. Slip Dovetail and the other as a Slip Key. The former is done by cutting a dovetail notch in the angle and driving in a dovetail key, afterwards cutting off the ends, the latter by making a saw kerf and gluing in a thin piece of hard wood.
No. 4 is termed a Box Rebate, and is substituted for a mitre when a rounded angle is required. It is secured by nailing.
No. 5, a Rebated Joint, is secured by nailing.
No. 6 is a Groove and Tongue Joint.
No. 7 is another form of the same, with moulded edge to hide the joint.
No 8, Return-Bead and Rebate Joint.
No. 9 is used for jointing two pieces of unequal thickness, and is called a Stopped Mitre.
Nos. 10 and 11 are respectively Lipped Mitre and Lipped and Tongued Mitre. Both may be adopted for uniting unequal thicknesses.
No 12 is a Tongued Mitre.
No. 13 is a Double-Tongued and Beaded Joint. It should be glued and no nails shown.
No. 14 is an adaptation of the same joint to an obtuse angle.
No. 15 is a very useful joint, also for an obtuse angle. It is used in high-class work, is not difficult to make, and must be glued. It is called a Double-Tongued Mitre.
No. 16 is a Rebated Mitre Joint for obtuse angles. The angle may be moulded to hide the joint.
No. 17 is a Lipped Mitre and Dovetail, useful in cases where two pieces of different directions of grain meet.
No. 18 is a joint largely used in packing cases. It is machine made, very strong, and is called Corner Locking.
No. 19 is the ordinary Packing Case or Box Dovetail Joint.
No. 20 is a Lapped Dovetail, or Drawer front dovetail, used in constructing drawers.
No. 21 is a Mitre or Secret Dovetail, used for external angles in high-class work.
No. 22 is a strong common dovetail joint, known as Cistern Dovetail, chiefly on account of its being used in the construction of wooden cisterns.
No. 23 shows the dovetail joint adapted to obtuse angles.
There are several forms of the mortise and tenon joint shown here. It may be noted in passing that when setting out mortises and tenons, lines indicating mortises should always be marked in pencil, while shoulders should be marked with a knife cut.
No. 25 is a Slot Mortise and tenon. It requires either pinning or screwing, and is only used in common work.
No. 26 shows the proper mortise and tenon.
No. 27 is a Haunched Tenon, a part of the tenon being cut away, the stump remaining at the root of the tenon being called the Haunch.
No. 28 shows a Stump Tenon, the tenon in this case being employed to keep the shoulder up, and the Stump, being much stouter, to take the strain.
No. 29 is called a pair of single tenons, and
No. 31 shows a Hammer- Headed Tenon, used principally for framing posts to circular-headed frames.
No. 32 is a joint used for connecting transoms in wide framing. It is called a Dovetail Tenon. In fixing, the mortise must be made long enough to allow the tenons to pass each other. When lapped, the mortise is closed and the tenons secured with a pair of folding wedges.
No. 33 is a Table or Taper-Haunched Tenon.
No. 34, a Tongued-Shoulder Joint, is preferred by many to double tenons in thick framing.
No. 35 is a joint employed in high-class work when it is not desired that the end of the tenon should show through. It is called a Fox Tenon or Pox Wedging. It requires very careful fitting. The mortise is first cut to the proper depth, and uniform. The tenon must be cut slightly shorter than the depth of mortise, and must fit tightly at the shoulder, otherwise it may split when cramped up. The wedges should be of slight taper, planed smooth, and out of hard wood, the outer ones rather longer than the inner, and be just thick enough to split the tenon but not beyond the shoulder. When putting together, the mortise, tenon, and wedges are well glued and the joint cramped up steadily but without stopping.
Nos. 36, 38, 39, and 40 are other methods of obtaining the same result.
Nos. 41, 42, and 43 show three methods of keying up butt joints: the first, known as a Dovetail Key, or Double Dovetail Key; the second, a Hammer-Headed Key, frequently used in segment framing; and the third, a Counter Cramp, used for wide boards, stair strings, etc. To make this joint, three strips of wood are fixed across as shown, the outside pieces screwed to one board, and the middle piece to the other, key ways having been previously cut in each as dotted, that in the middle piece being fixed nearer the joint. Folding wedges are then driven through, and when the joint is up it is secured by screws driven in at the points marked x .