How do I account for seasonal movement in raised-panel doors?
After reading about the effects of moisture on wood movement, I'm reluctant to try tablesawn raised panels. Won't the wedged edges of the panel spread the grooved stile to the breaking point, especially on wide panels?
—Michael Boles, Columbus, Ohio
Fortunately, Michael, time-tested, raised-panel construction absorbs the often punishing effects of seasonal wood movement by capturing the movement-prone panel in a forgiving frame. The wedged edges of Shaker-style, tablesawn panels might be a little less forgiving than other designs, but the steps to avoid wood movement catastrophes are the same.
First, make your panel from straight-grained, rift-sawn or quartersawn wood that has been properly kiln-dried—which is less prone to movement than cathedral-grained wood. Once in your shop, let the wood acclimate for a couple weeks before machining it. This allows the wood's moisture content to stabilize with its surroundings.
After measuring between the grooves in the rails and stiles, cut the raised panel to leave at least a 1⁄8 " gap on all sides. This leaves the panel free to shrink and swell with the changing humidity of the seasons. To avoid a loose or rattling panel, install flexible spacers, such as "Space Balls" (Woodcraft #142284, package of 100, 800-225-1153), in the grooves, or glue or pin-nail the top and bottom center of the panel in the rail. For panels 18" or more wide, or if the piece will experience drastic changes in humidity, such as a cross-country trip from Arizona to Florida, deepen the grooves and/or narrow the panel to allow for even more swelling.
Finally, panel shrinkage might expose a slight gap between the panel profile and the stile groove in tablesawn panels, so stain and finish the panel before inserting it in the frame to avoid a distracting unstained line.