How to Make Bookcase Dadoes

Since the advent of handheld routers, woodworkers no longer dread making dado joints. The days of making a pair of rough cuts with backsaws and then cleaning out the waste wood between with chisels are gone. Now all we have to do is make a single pass with a router, and we have a perfectly sized dado joint, ready for use.

There are several ways to make a bookcase dado using a router, but this method is simple and requires only common woodworking tools.

Things You'll Need

• Router
• Router bit, same thickness as the shelves
• Pencil
• Carpenter's square
• Straight piece of 1 x 4
• Clamps
• The shelves and sides for your bookcase

Instructions

1. Install the router bit in the router's chuck, and adjust the depth of cut (per your manufacturer's instructions) so that the bit will cut a dado a third to a half of the way into the shelf.

2. Lay the two sides of the bookcase side by side on your workbench, lining up the bottom edges so they are even. Clamp the sides to the bench.

3. Decide where on the sides you want the shelves to be. Place one shelf against the edge of one of the bookcase sides, and make two pencil marks on either side of the shelf, outlining its thickness on the side.

4. Make a single mark halfway between the two marks; this is the centerline of the shelf. Use the carpenter's square and pencil to draw a straight line through this mark, extending it all the way across both sides of the bookcase.

5. Measure a distance equal to half the width of your router's base from the centerline you just drew, and mark this distance on the bookcase side. Repeat at the other end of the centerline.

6. Use these two marks to line up the 1 x 4 parallel to the centerline, and clamp it in place. The 1 x 4 will serve as a guide for the router.

7. Place the router on the side pieces, with one edge of the router base against the 1 x 4 and the bit close to (but not touching) the side piece.

8. Start the router and push it across the two side pieces, keeping the router base against the 1 x 4. You will rout a perfectly straight dado across both sides of the case.

9. Repeat the process for each shelf.

Tips & Warnings

• If you do not know the width of your router's base, you can probably use the router itself to measure where the 1 x 4 should be clamped. Most routers have an aiming mark on the front of the base. You can hold the router against the side piece, with this mark aligned on the centerline you drew across the sides, and mark the outer edge of the base.

• Do not start the router while the bit is touching the wood. This may cause the router to jerk out of your hands and cause injury.

References

• New Woodworker: How to Cut Dados
• Woodworking Tips: Custom-Fitting Dados

Resources

• Router Dado Jig
• Cutting Dados with a Jig