Wooden surrounds come in many different sizes, the most common to turn are for 8”, 10”, 12”, 14”, 16” & 18” clock dials. All surrounds are turned from period mahogany and tend to be one piece. The brass bezel would be required to ensure a precise fit, the surround would then be morticed to accept the hinge & tab. I can turn any size surround up to approximately 24” in diameter.