The procedures in this article are standard practices for bench jewelers at this time. If not executed properly, however, they can cause harm. Neither the author nor the publisher is responsible for injuries, losses, or damage that may result from the use or misuse of this information.
Safety Alert: Burs and other setting tools are extremely sharp and, if used improperly, can cause serious injury. Be sure that your hands are firmly secured and safely protected at all times.
Among all of the jewelry items and objects that can be made by hand, the locket is one of the most complex and practical. Unlike nearly all other jewelry, lockets serve a function. Like wearing a small safe, a locket can protect and conceal valuables, pictures, human hair, mementos, and even medication.
1. This basic locket is composed of two domed halves with removable bezels so that a photo can be inserted on each side. The halves are hinged together and held closed with a friction catch. A bail is added so that the locket can be worn on a chain. Modifications to this basic pattern can include making the locket oval or heart-shaped, adding knuckles, adding pages inside, hinging it from the top, etc. The project is made almost entirely of 0.6 mm sterling silver sheet. Note that firecoat (boric acid and alcohol) is used whenever possible to protect the silver surfaces from firescale.
2. Mark and saw out two 27 mm disks from 0.6 mm sheet. There is no need to trim or file to the marks at this point.
3. Apply firecoat and anneal the disks if they are not already soft. Use a dapping (also called doming) block as the die and a punch to shape the metal. Most steel dapping blocks are deep and half-round. This wooden one is intended for watchcases and has shallow domed depressions. The matching wooden punch also has a low dome on the front end. Gently tap the punch to push the metal all around, rather than slamming it in one spot. Alternate working on both domes so they match. Measure the heights of the domes to compare. Stop when the two pieces are 4.5 mm tall.
4. Use a large flat file to establish a flat surface around the base of each dome (i.e., where they meet when held together). Alternate filing on both pieces until they have large, uniform flat rims.
5. On another piece of 0.6 mm sheet, lay out two 21 mm holes for the bezels. When domes are placed over the holes and soldered, each side will have a frame for the bezel 3 mm wide. With dividers, lay out two 21 mm circles on the sheet, with a border of at least 4 mm.
6. After piercing the 21 mm holes, correct the shape with a half-round file. Finish the holes by using an inside ring sanding cone with coarse paper (220 grit or lower). These wooden tapered mandrels are intended for use at low speed on a polishing lathe, though they are also effective by hand. An alternate method is to wrap a ring mandrel with coarse paper. Twist the sandpaper into the hole until the surface is uniform and round. Measure the holes; make sure they are round and identical in size (21 mm). Set the pieces aside.
7. Make two bezels that will fit into the half domes to hold photos. The bezels should be perfectly round and fit exactly into the 21 mm holes. To calculate the length of the blanks for the bezel strips use this equation. (Note:O.D. refers to the outside diameter of the bezel.)
? (O.D. – thickness) – 0.5 mm = bezel length
3.14 (21 – 0.6) – 0.5 = 63.5 mm
Because it is easy to stretch a bezel, lay out the blank 0.5 mm too short as indicated so that it can be stretched up later. Cut two strips of 0.6 mm sheet, 2.5 mm wide and 63.5 mm long. Flatten the ends with a file and make sure there are no burs. Use half-round pliers to bring the ends together for soldering.
8. Clean and flux the seams, then solder the bezels closed with hard solder. Use two mounted tweezers to set up both bezels for soldering at the same time. Quench, pickle, rinse, and dry.
9. Round the bezels on a ring mandrel. At first they should be too small to fit into the holes, because of the 0.5 mm taken away from the blank. This makes it easy to stretch them to fit tightly into the holes. Anneal the bezels; check again; make sure they are round. File one side of each bezel flat and remove burs by sanding.
To prepare the base plates for the bezels, cut two 27 mm squares from 0.6 mm sheet. Bend down each corner using flat-nose pliers, taking care to keep the center of the sheet flat. Firecoat and place on a white reflective soldering pad. Flux the flat side of each annealed bezel and place on the center of the sheet. Use binding wire to gently hold the two assemblies in position. Place snippets of hard solder on the inside of each bezel where it meets the sheet. Aim a neutral flame at the soldering pad toward the front of the base plate, holding at a 45-degree angle; this will bounce heat up under the bezel. Continue to heat and move the flame around the bezel until solder flows. Quench, pickle, rinse, and dry.
10. Use a saw to remove the excess around bezels.
11. Use a flat file to trim the excess sheet flush with each bezel. Use long strokes with the file rolling away from you, at the same time pivoting the work toward you on your bench pin. Correct the surfaces on the outside of both bezels, being very careful not to remove too much metal. These two bezels must still fit tightly into the pierced holes in the sheet after filing, sanding, and polishing, so go lightly with the file.
12. Prepare the two pieces of sheet with the 21 mm holes to be soldered to the two domed halves. To position them correctly, inscribe two guide circles around the holes on one side of each sheet. Do this by setting the dividers at about 4 mm. Rest one leg inside the hole as the other inscribes a circle around it on the surface. Clean, firecoat, flux. On a charcoal block, position the dome centered in the guide circle. Use binding wire to hold the parts in place; position snippets of hard solder generously around the dome, resting on the base plate.
13. Use a large neutral flame to join each domed half to the base sheet. Add solder as needed and test for complete flow by dragging a solder pick along seams, as the solder is liquid. Quench, pickle, rinse, and dry.
14. Trim the excess with a saw, and then file the two halves until they are round.
15. After the bezels have been soldered to the bases and trimmed (steps 8, 9, and 10), use dividers to lay out a circle 2 mm within the exterior. Pierce and remove the centers. File interiors round using a half-round file.
Excerpted from Professional Jewelry Making by Alan Revere (Brynmorgen Press, © 2011). Look for Part 2 in the October 2012 issue of JCK.