The Technique of FURNITURE MAKING

Chair construction

Traditional chairs were normally framed together with mortise and tenon joints, for dowel-pegs had to be hand-shaped and boring - bits were primitive. Modern chairs rely more on dowelling techniques, and there can be no valid objection to this providing the pegs are of sufficient length to hold the joint. The usual procedure is to make up the front and back frames first, and then connect with the side rails unless a knock-down assembly is used. All chair-work requires accurate full-size drawings from which the correct angles and bevels can be taken, and more elaborate chairs really need a full-size working model or prototype in softwood which can be tested and altered as required.

Chair joints

Top back rail joints are illustrated in 466. Figure 466:1 is a tenon on the rail, 466:2 shows a tenon on the post, and 466:5 a dovetail bridle joint. Where the wood sections are very slim (466:6) the joint can be reinforced by forming a step to

support the back thrust and increase the gluing area. Figure 466:3 shows a shaped post and top rail mortised and tenoned together and rounded after assembly. In 466:4 the top dowel has no real holding power but does prevent the top twisting out of line, while dowels are also used in 466:7 where it might be difficult to accommodate a tenon in the curve of the back post. The shield back chair in 466:8 and Chippendale carved chair in 466:9 are shown as a matter of interest only, for the heavy carving usually disguises the line of the joint, as shown by the dotted lines. A modern treatment in which a bowed, tilted and rounded back rail meets turned back posts is shown in 466:10-12, with 466:10A the front view and 466:10B the back view. Figures 466:11, 12 show the actual joint and the amount of material left on to accommodate the dovetail. The joint must be carefully laid out and worked with the final rounding and shaping done when the rail is fully assembled. This type of construction is very expensive, therefore, and confined to the best handwork only. Figure 466:13 shows a mortise and tenon joint at the junction of front and side seat rails with the front leg. Either a canted tenon or a canted mortise is necessary for the latter; therefore it is more usual to tenon the front rail and dowel the side rail (466:14), in which it is comparatively simple to bore the leg at the correct angle obtained from the full-size drawing. The outer face of the leg is usually planed off after assembly to the line of the rail, as indicated by the dotted lines in 466:13. Back seat rails are normally tenoned into the back posts. Where a rail meets a rounded leg (466:15) a small flat can be worked for square-cut tenon shoulders, but if the rail is also rounded then the leg recess must be scribed to fit. Here again it is simpler to use dowels, cutting the rail end square, marking and boring for the dowels and scribing the rail shoulders to fit the leg before the dowels are glued in (466:16). Figure 466:17 shows a turned spindle entering a round leg. and if a bung borer (taper bit) is available then the spindle is turned to fit the taper, taking care to ensure that the socket depth is correct, for there will be no shoulder to limit the entry. Parallel­sided sockets bored with standard bits will require a turned shoulder on the spindle and a small flat formed on the leg, but in cheap work the taper spindle is merely driven into the parallel hole, with the result that it only bites at the neck. In 466:19, where a pronounced hollow is formed in the leg, it will be easier to use dowels, marking, boring and then fitting the rail to the leg before the dowels are inserted. An improved method of jointing side rails to back posts sometimes adopted in Scandinavian furniture is shown in 467 but it is essentially a machine operation.

The junction of arm rests with leg posts is shown in 466:20 where a small stub tenon can be used, although a single dowel is often effective, for the strain is upwards and not sidewards. Traditional chairs with turned legs and flat arm rests employed a spigot end to the leg taken through and wedged from the top, as 466:22, while 466:21 is the jointing of a typical modern framework where the overall angle is halved and dowelled together. Figure 466:23 is the juction of arm post with side rails in conventional armchairs, with the arm post housed/grooved in and screwed from the inside, and 466:24 the connection with the back post with stub dowel to take the pull. Older examples were often housed in and screwed and pelleted from the back (466:25), while 466:26 is the junction of a downward curved arm rest tenoned in and housed at the top to avoid a feather edge in the final shaping after assembly.