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Prepare the Pieces
1. Glue up boards, if necessary, to make stock for the wide top (A, Fig. A, below) and legs (B). Plane this stock to final thickness, along with a piece for the rail (C). Mill extra stock for test cuts and the keys (D) to the same 1-1/8-in. thickness. Your stock must be dead flat when you rout, and also when you assemble the pieces, for the dovetail joints to fit well and slide smoothly.
2. Rip the top, legs and rail to width; then crosscut the ends to length. Make sure the cuts are square.
Rout the Sliding Dovetails
3. Build the socket-routing jig (Fig. B, below). Use your top (A) to establish the width between the jig’s rails. To make sure the fences are spaced properly during assembly, fit a piece of scrap ripped to the proper width between them.
4. Establish the dovetail sockets in the jig’s rails by setting the dovetail bit to 3/8 in. exposure and routing a test socket in extra stock. Mark the centers of the sockets in the rails.
5. Mark the socket locations on the edge of the top. Then position the jig by aligning the socket centerlines. Clamp the jig and the top securely to your workbench. Make sure the jig’s rails are flush with the top. If they protrude, the router base will catch on them and cause trouble.
6. Rout the sockets (Fig. A, Detail 1) in a clockwise loop, bearing against the left fence on the way out and the right fence on the way back (Photo 1). A dovetail bit with a 1/2-in. shank produces smooth, chatter-free results. If your dovetail bit has a 1/4-in. shank, rout clearance channels first, with a 1/4-in. straight bit.
7. Rout dovetails in the leg blanks on your router table, with a tall fence installed for support (Photo 2). Set the bit’s height so your dovetails are no more than 1/64 in. shorter than the depth of the socket. If the dovetails bottom out, the joint will be much harder to slide together.
To find the exact fence setting, start by routing an oversize dovetail. Then adjust the fence to make the dovetail smaller. Each adjustment has a double effect on the dovetail’s width, because you rout both sides of the leg. For a cool way to make the tiny adjustments that are necessary to dial in a perfect fit, check out Photo 10 in “Router Table Box Joints”.
During assembly, you’ll slide home both dovetailed legs simultaneously, so the dovetails need to have a little bit of slack when you fit them individually. The dovetails fit properly when you can slide each one home smoothly, with hand pressure only. If you have to use a mallet, they’re too tight. If they rattle, they’re too loose and you’ll have to start over.
When you think you’ve got the fence set just right, rout one more test dovetail. Make one pass on each side of a fresh blank and test the fit. If this dovetail slides smoothly with hand pressure or needs only minor adjustment (Photo 3), you’re good to go.
Fit the Half-Lap Joints
These joints must fit snugly; assembly should require firm hand pressure.
8. Mark the notch locations on the rail (Photo 4, Fig. A). Use a sharp pencil, so the lines on the rail accurately indicate the thickness of the legs. Cutting to the inside edges of these lines creates notches that are the same thickness as the legs.
9. Mark the notch locations on the leg blanks—these notches are centered. Use the rail to mark their width.
10. Saw the notches in the rail, using the miter gauge with a long fence attached (Photo 5). Although it’s tempting to saw right to the lines, it’s better to play it safe by cutting short first and then trimming (Photo 6). The notches in the legs are deeper (Photo 7), because the rail has to sit even with (or slightly below) the dovetail shoulders (Photo 8).
Assemble
11. Drill screw holes in the rail on your drill press. Use a fence to center the holes and support the rail. First, drill the 3-1/4-in.-long counterbores with a 7/16-in. brad-point bit. Flip over the rail to drill the 11/64-in. pilot holes.
12. Saw arches in the rail and arches and tapers in the legs (Photo 9, Fig. A). Smooth the arches with a sanding drum installed in your drill press. Smooth the tapers by jointing, hand planing or sanding.
13. It’s easiest to sand all the surfaces smooth and break all the sharp edges before assembly. Be careful around the edges of the dovetail sockets and just below the half-lap notches—sanding these areas too heavily will loosen your joints. From now on, keep your bench covered to protect the sanded top, so it doesn’t get scratched.
14. Dry-fit the base and top to make sure the dovetail joints slide and the rail doesn’t bind against the top.
15. Center the base and mark its location. Then slide it a couple inches off center and apply glue (Photo 10). Slide the base home. Keep a mallet handy, in case the glue swells the joints enough to require a little extra persuasion. Fasten the base to the top with screws through the rail.
Make the Tapered Keys
16. Cut the dovetail-shaped keys from a wide blank, oriented so the faces will show end grain. (Photo 11; Fig. A, Detail 2). The tapered sides match the 14-degree slope of the dovetail sockets. Leave the keys a hair wide so they’ll still fit snugly after you’ve sanded them smooth.
17. The faces of the keys bevel at different angles, so two setups are necessary (Photo 12). After the faces have been cut, rip the completed keys from the blank (Photo 13) and fit them to the sockets (Photo 14).
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Photo 1: Sliding dovetail joints are the key to this project, and the best way to make them is to start with the sockets. It’s easier to fit dovetails to sockets than vice versa. In this bench, the sockets must be consistently wide and parallel to one another. These requirements are easily met with a shop-made routing jig (Fig. B).
Photo 2: Rout dovetails in the leg blanks by making a single pass on each face. You’ll have to creep up on the perfect bit height and fence setting by trial and error. Make test cuts on an extra leg blank. Your goal: Dovetails that slide into the sockets smoothly with gentle hand pressure.
Photo 3: Fitting sliding dovetails is fussy. If routing leaves yours a bit tight, a little sanding may do the trick. Lightly sand one bevel (on either the socket or the dovetail) end-to-end, being careful not to alter its angle, and test the fit. If the joint is still too tight, sand another bevel and test again.
Photo 4: Mark the rail for the half-lap notches. They have to be perfectly located, so don’t trust your tape measure; use the real bench. Slide the legs into the sockets and clamp the rail to them. Make sure the rail is centered and the legs are perpendicular to the top. Then mark both sides of both legs on the rail.
Photo 5: Saw notches in the rail. Cutting deep notches like these is less nerve-wracking on the bandsaw than on the tablesaw. Glue sandpaper to your miter gauge so the rail doesn’t slip during the cut; cut well inside the lines and then remove the waste.
Photo 6: Trim to the lines. A sharp blade on a well-tuned bandsaw can remove a whisker from the edge, just like a tablesaw can. Nibbling off a little at a time is much less risky than going for broke. Test the fit after each nibble.
Photo 7: Saw notches in the legs, using the same approach as with the rail (Photos 5 and 6). This time, trim to the lines by tweaking the position of the fence.
Photo 8: Test the half-lap joints to see whether the notches are deep enough. You’re good to go when the top of the rail is even with the dovetail shoulders.
Photo 9: Saw arches and tapers in the legs. Tip: For sawing smooth tapers, start at the shallow end, allowing the blade to gradually bite into the edge. If you start at the wide end, the blade is likely to break out as it approaches the shallow end, leaving a bumpy edge.
Photo 10: Apply glue to the sockets in front and the dovetails behind, after sliding the assembled base within a couple inches of its final position. Then slide the legs home. It’s risky to glue sliding dovetails full-length. The tolerances are so close that they’re likely to get stuck before you can push them all the way.
Photo 11: Dovetailed keys fill the ends of the sockets. The secret to making them safely is to keep them attached to a large blank while you make all the angled cuts. First, saw the tapered sides. It’s best to make these deep cuts in several passes, rather than all at once.
Photo 12: Crosscut the faces of the keys on the bandsaw. Cut all the back faces, reset the miter gauge and cut the front faces, which bevel at a slightly different angle.
Photo 13: Free the keys with a rip cut. Making this cut on the bandsaw eliminates the risk of dangerous kickback that exists whenever you cut small pieces on a tablesaw.
Photo 14: Fit the keys. Remove saw marks and fine-tune the fit by sanding. Before gluing the keys in place, I highlighted them with a dark stain. By attracting attention to the hidden joinery, these keys become the focal point of the bench.
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