To turn the edge.
-- To turn the edge scribe a mark the width of the edge and proceed to hammer lightly around the edge using anvil,burnisher and hammer,work slowley forming the edge and the curvature until it is slightly more than the guitars sound hole the ends should overlap. To install the tornavoz in the recess inside of the sound hole,squeeze and roll it in ,to remove insert removal hooks into holes in tornavoz and twist out. The removal hooks are made of heavy metal coat hanger material and the thickness of the tornavoz brass is about the same thickness of a matchbook cover. Practice making a tornavoz from scrap sheet aluminum left over from making your templates. Use brass to be historically correct as aluminum is a new metal and not in use in the time of Torres. The tornavoz is an early attempt at improving the projection of the guitar. The original tornavozes were installed permanently and could not be removed,having small notched posts ito which the lower edge of the tornavoz sat this method gives you the option of removal.