Allowing for Expansion in Door Panels

Tips on sizing raised door panels to allow for wood movement. February 26, 2007

I am starting to build raised panel doors using standard cope and stick router bits that cut a 7/16" cope and panel groove. I cut my raised panels so that there is a 1/4" space for expansion at each stile. My question - what is the maximum width I could make the raised panel and not have the door fail due to expansion exceeding 1/2' across the width of the panel?

Forum Responses
(Cabinetmaking Forum)
From the original questioner:
I gave incorrect dimensions above - my panels allow for 1/8" movement on each side for a total expansion of 1/4" across the panel. I am looking to find out what the largest width panel I can make without exceeding 1/4" total expansion.

From contributor J:
Check out the lumber/timber calculators on the main page of this site. Red oak will move as much as 1/4" per foot of width with changes in humidity. I'd say if you use this as a measuring device, you'll be in good shape. My shaper cutters cut a 3/8" groove and I try to keep everything under 16". I have not had a problem in hundreds of doors.

From Gene Wengert, forum technical advisor:
In the extreme, you might see an increase of 7% MC from when the panel is manufactured. Use this value with the calculators here.