The Technique of FURNITURE MAKING

Lapped dovetails

This is the usual type for drawer sides (154:4), carcass-work (154:5), etc. where one face must not show the joint and the dovetails are set back by a small lap or lip. Setting out and working is the same as for through dovetails, but the full thickness of the tail side must be gauged on the inner face of the pin side only, the width of the lap or set-back determined—3/16 in (5 mm) in 3/4 in (19 mm) thickness is usual but not mandatory—the gauge reset and the lap gauged in from the inner face of the pin side and all round the tail piece. Figure 154:4 shows a typical setting out for a drawer side with two widely spaced whole pins sufficient for an average drawer up to say 6 in (152 mm) deep, and three pins for larger drawers; while 154:5 shows coarser carcass dovetails connecting, for example, a carcass top to a side. Small dovetails are provided at front and back to prevent any twisting of the panel edges, but the main dovetails can be widely spaced with the tails about two and a half times the width of the pins as a fair average. Sawing in the tail sockets on the pin piece can be done as in 154:8, while most of the waste can be cleared with the saw or bored out as in 154:12; the remainder is then chiselled out as shown, again bevelling inwards as in the inset. In all setting out so far described for both through and lap dovetails no allowance has been made in lengths and widths for cleaning off, and this must be at the discretion of the worker. If the jointing is good only a thin shaving will be required to flush the surfaces and provide a smoothly running drawer, but if the worker is uncertain and wishes to make allowances then he must set his gauge-marks in accordingly. As with all woodworking activities the only true guide is positive experience, often bitter but nevertheless inevitable. On no account should dovetails be 'bishoped', i. e. hit with a hammer to spread the fibres and tighten up a slack fit. If there are gaps between the tails and pins—and it can happen to anyone—then it is perfectly legitimate to drive in small glued wedges of matching end grain which, if neatly done, will be invisible. Very tall carcass sides which carry the pins cannot be held in the vice for marking, and therefore the pins must be worked first and the tails marked from them with a scriber or knife point, as with secret lap and secret mitre dovetails.