Furnished content.
(from Lumberjocks.com)
For the past 20ish years I have challenged to make stuff with wood that does not require screws or nails. It's just a mental challenge I enjoy. Dovetails, mortise and tenons, and sliding dovetails are my friends in this challenge. The problem is, sliding dovetails are usually a pain to get right and they are not very forgiving if I make a mistake.That changed when it hit me that a simple guide rail cut with a dovetail bit at the exact same depth as the thickness of the guide(photo 1 and 2), will create a profile (housing) that exactly lines up with the wide part of the dovetail at ANY depth needed (see red lines in photo 3). So I made two identical guide rails using the same bit that I make the dovetail with. The finished project here is the pair of guides. Each made from 1/4” thick plywood base and a plywood (thickness not critical) rail with a straight edge for the router to ride along.With a pair of these guides, the process of making the sliding dovetail is pretty simple and reliable.1. Use the dovetail bit to cut the long dovetail. It does not matter if the dovetail is tapered or the same width throughout. Can be done with handheld router or a router table.
2. (Photo 4) Position the first guide rail on the wood where you need to cut the dovetail housing and clamp it in place good. It must not move.
3. (photo 5) Position the dovetail board you made in step 1 firmly against the guide rail in the position that you need the board to end up.
4. (photo 5) Push the other guide rail firmly against the other side of the dovetail and clamp it firmly in place.
5. (photo 6) Slide the dovetail board the end being careful not to shift the guides. Then set your router to the depth of dovetail PLUS the thickness of the base of the guide. And run it along the left guide, then run it back along the right guide (this avoids a climbing cut)
The housing matches the dovetail exactly. If you set the depth right, it will be a perfect fit.Super simple game changer if you use sliding dovetails for shelves or battens.source: More photos and build description of simple sliding dovetail jig.