I recently completed a commission for some medieval style thrones, each with several panels carved in low relief. Each panel had large areas of flat background. In order to complete it in a reasonable time and with decent flatness, I resorted to using my overarm router to clear most of the panel before hand carving the actual design:
Here's the router--a Duro, circa 1950.
First panel, with star pattern and the background routed out:
This panel is 7" x 35" and started out 3/4" thick. There are 22 stars.
Each throne also had a triangular panel:
On all these panels, I used a shallow fishtail gouge to clean up the router marks. Since the overarm router table was much smaller than the long panels, I wasn't entirely successful in keeping the panels from tilting. So there was some digging in.
And assembled:
Kirk