One measure of the security of a joint is how far it must move before it disconnects. A second measure is the direction of disassembly relative to the load. A simple housed dado joint has a grip of less than an inch. The main load is downward, but sides only have to bow out or the shelves bend a little before the books go tumbling down.
The sliding dovetail keeps your books on the shelves by keeping the direction of disassembly perpendicular to the load. It has to be withdrawn six inches or so before it could let go, but even then, the load still pushes the hooked elements together.
The sliding dovetail is found in batten form under plank chairs and table-tops and in the joint between the legs and the pedestal of small tables. Longer sliding dovetails, such as those made to join broad boards in shelving are best made tapered. This allows the joint to fit up easily until the very last, when the wedging action draws the joint tight.
In casework, the top of the shelf is left square and only the lower edge dovetailed and tapered. In other applications, such as making benches or boxes, orient the square shoulder to the weakest end—the end with the least wood. The sliding dovetail is meant to get tight only on the last tap of the mallet, but it can still act as a wedge on that last tap. The square face pushes squarely along the grain, but the dovetailed face pushes and lifts, and can more easily split the board that it is driven into.
Mark lines across the side board the full thickness of the shelf. Set your marking gauge to less than half of the thickness of the side and mark the depth of the housing on the edge; then use the same setting to mark the shoulder of the dovetail on the shelf.
Set your sliding bevel to a one-in-five-inch angle, a little steeper than the usual dovetail, and use it to mark up from the lower corner of the housing on the edge to find the starting place for the long slope. This slope is perhaps a quarter inch in eight. Strike it and the upper, square shoulder with a chisel or marking knife.
Before you start sawing, use the sliding bevel to make an angle guide for your saw from a block of scrap wood. You can cut the sliding dovetail socket with saws and chisels, just as you did the dado. If the sliding dovetail is through, and not stopped, a side rabbet can help you smooth the undercut.
For the dovetail on the shelf, first plane the taper across the grain with a fillister. You can then saw and chisel the dovetail using a guide block cut at the reciprocal angle left on the sliding bevel. Continental European joiners use this joint a lot, and have a special dovetail plane shaped like a rabbet plane with an angled sole. Not by coincidence, the sliding dovetail joint is much like the full dovetail log joint used by Moravian builders. The log joint doesn't slide, but it slopes in two directions at once, and it looks a lot harder to cut than it really is.
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There are a lot of things that either needs to be repaired, or put together when youre a homeowner. If youre a new homeowner, and have just gotten out of apartment style living, you might want to take this list with you to the hardware store. From remolding jobs to putting together furniture you can use these 5 power tools to get your stuff together. Dont forget too that youll need a few extra tools for other jobs around the house.