By using a basic dovetail jig on a router table—rather than with a handheld router—you can turn out four perfect-fitting joints in about 12 minutes.
Start with the right jig
Over the years, we've used four jigs to cut through-dovetails on a router table. [See Sources, on last slide.] They all work essentially the same and come with everything you need, including bits. The Leigh and MLCS jigs use guide bushings to steer the bit between the template's guide fingers. But we prefer the jigs that use bearing-guided bits—Katie Jig and Keller—because they're easier to set up and change bits.
With all but the Katie Jig, which comes ready to use, you'll first need to mount the finger template onto a backer board and make a one-time calibration for tight-fitting joints. (Each jig's instructions explain how to do this.) The backer board not only secures the jig and registers your workpiece properly, but also provides support on the back side against grain tear-out.
Scribe a centerline on the top side of a finger in the middle of the jig, photo above, on both the pins and tails side. This will be used to center boards for symmetrical joints.
Now, rout the joints
Cut your project parts to size with square ends—and a couple of extra pieces for testing setups. When cutting dovetails with these jigs, tailboards and pinboards don't have to be the same thickness, but opposing boards in a drawer or other box do need to be of equal thickness. Arrange the boards to form the project, with the best faces out. Mark the outer faces -- this proves critical when routing the pins—as well as the joints with sequential numbers or letters so you can match them up after machining. Now you're ready to begin cutting as shown on the following slide, tails first.
Scribe a centerline
Use a small square and craft knife to scribe a line down the length of a center guide finger on each side of the jig.
Mark for thickness
Mark the tailboard thickness on one pinboard; then use the pinboard to mark its thickness on the tailboard.
Set the tail-bit height
Lay out a centerline on the tailboard, align it with the jig's centerline, and clamp in place. Raise the bit 1⁄32 " above the thickness line.
Add a stopblock
Clamp a stopblock next to the tailboard to make repeatable dovetail cuts on this and other tailboards.
Rout the tails
Cut the tails by guiding the jig into the bit, so that it slides between the straight guide fingers. Repeat for each tailboard end.
Mark the tail sockets
Stand a tailboard on a pinboard and transfer the tail locations. Wood visible between the tails will be pins; you'll rout away the sockets.
Switch to the pin-cutting bit
Install the straight bit and set its height as before. Lay out a centerline of one marked pin and align that to the scribed finger.
Rout the pins
Clamp the pinboard with its inside face against the jig, set the stopblock against the board, and rout the tail sockets to make pins.
Test fit for alignment
If the test joints don't line up perfectly, slide the pinboard half the difference left or right, readjust the stopblock, and rout new pins.
Tap together for a perfect fit
With all tails and pins cut, dry-fit the box; tap parts together lightly with a mallet to avoid any damage to the joints.
Keller jig: #1500 Journeyman (1⁄4 "-shank bits only), Keller Dovetail, 800-995-2456, kellerdovetail.com.
MLCS jig: #6412 (1⁄4 "-shank bits), #8712 (1⁄2 "-shank bits), MLCS, 800-533-9298, mlcswoodworking.com.
Leigh Jig: #R9 Plus (8mm-shank bits, collet reducer included), Leigh Industries, 800-663-8932, leighjigs.com.
Katie Jig: #KJ1-12000001 (38"-shank bits, collet reducer included), Katie Jig, 317-787-1965, katiejig.com.