With the frame stock squared four sides I turned my attention to the panel stock. These started out as long 8/4 boards over 12 inches wide, they were resawn into roughly 1″ thick panels but have heavy machine marks on them and significant twist and cupping. The finished panels need to be 1/2″ thick and completely flat.
I started out ripping the pieces to just under 12″ wide to remove a little of the twist and also to allow them to fit through my thickness planer. I then used a scrub plane to take out enough twist to prevent the panel rocking. I finished with multiple passes through the thickness planer to flatten the faces and take the panel down close to final thickness.