If brass, the plate should be thoroughly annealed by heating to red and either let air cool or dunk in water. Lay out the hinge segment widths and determine the preliminary segment depths...deep enough so that the segment can be bent w/o tearing. Each segment should be long enough to allow for excess length for later riveting or soldering.If solder is intended, sand the inside surfaces of the segments before forming. Saw out the gaps leaving excess mat'l outside the layout lines. Take a 1/16" steel plate that's long enough to accommodate the hinge and file a full radius on one edge. Clamp both the 1/16" stl plate and brass and bend each segment to 90 degrees using a hardwood block to ensure that each segment is tight around the radius. Place a steel plate that's at least 3/16" thick against the vise jaw and clamp the 1/16" plate and brass against this plate but so that the 3/16" plate and the 1/16" plate and brass are high enough to bend each segment 180 degrees. Then clamp the 1/16" plate and brass upside down in the vise so the segments are flat against the 1/16" plate. Remove the 1/16" plate and replace w/ 1/16 dia. music wire that's 3X as long as the hinge. Clamp the brass and music wire lightly in the vise w/ the segments' open end facing down and eyeball so that the wire and knuckle tops are parallel to the top of the vise jaws and the vise jaws are in line as to where the knuckles end. Close vise tightly. The excess segment length is then riveted w/ the wire in the knuckles and if soldered, the wire is removed and each segment is clamped and soldered. The hinge pin holes are then drilled w/ a 1/16" drill to clear the solder. Then the knuckles {segments} of both the finial and lid are fitted together w/ a file. The stock sides of the inside knuckles are slightly angled so when the lid and finial are bent to the stock shape, they don't bind. Whew! This explanation takes longer than actually forming the hinge. Hope this helps...kinda hard to explain and there are other ways to do this, but I've found this works for me. If further info is needed, by all means contact me by PT...Good luck...Fred