Our Center /Offset Marking Tool straddles your board to mark a perfectly centered line along the face or edge of boards up to /2'' wide or thick. Just insert your. Center Finder - quickly and positively determines the center point of round or octagonal stock up to 8" in diameter sold at Highland Woodworking. Works quickly and accurately to locate the center of stock for turning on a lathe or other purposes. No need for special calculations. This easy-to-use finder has.