Cross-Grain Moldings

I’ve had a number of questions in my stories and posts regarding dovetailing cross-grain moldings so I figured, why not shed some light on it.

Wood moves. It’s a fact of furniture building and ignoring it will just lead to your pieces tearing themselves apart when the temperature or humidity swings a little. I suppose we could be gauche and use plywood but where’s the fun in that?

The moldings for these dressers were cove cut on the table saw and ripped to 1 1/2”. Next, the dresser top was checked for square - front to back, top to front, and to sides, all fine tuned with a plane until they register 90 degrees. The front is straightforward enough, since it’s a long-to-long grain glue joint. Some careful measuring and cutting 45’s and this piece is installed with cauls cut to the molding profile.

The sides are where things get interesting, as they sit cross-grain to the top. Wood expands a bunch widthwise but almost negligibly lengthwise, thus a standard glue joint will fail. To combat this, a 1/2” wide sliding dovetail is first routed into the side pieces and an appropriately sized key is fashioned from a wood species with a lot of strength but a little give - I prefer quartersawn Sitka spruce for the job.

I use my Amish jointer (a Lie Nielson No. 8 clamped upside down in my vise) to tune everything off the router, including cutting the keys about 0.010” shallower than the dovetail socket itself. A bit of machining on the drill press and the piece is screwed into the end grain using #6 × 3/4” countersunk stainless screws.

A ~1” offcut of the dovetailed molding is handy for checking alignment and making sure the piece goes on level across the 20” width. Waste cuts are made with a Dozuki saw between each pair of screws. I double check all angles and then the molding is slid on. That 0.010” undercut drawbores everything in nice and tight, and the softness of the QS Sitka spruce ensures the process goes smoothly. A bit of hide glue on the miter and the front ~1” of the piece, some light clamping pressure, and we’re ready for a beer!