As I have commented to many people, Debora can design and make necklaces faster than I can complete them with clasps. Sometimes she will also outstrip my ability to keep supplies up. Usually, I will use commercial clasps, because Debora prefers lobster claw style to toggles and other clasps. However, I ran out of yellow (gold color) clasps and she made a necklace with gold wire, so I needed to come up with a matching clasp. As with any creation, you should start with making a drawing of your idea. This allows you to see an image of your future creation. The drawing also allows you to see if your idea makes sense in terms of size. I decided to make a toggle type clasp based on interlocking ovals.
As you can see in these drawings, the style and size of the components will make sense and be workable. After making the drawing, you then need to transfer your idea to the metal that you will be using. I selected 26 gauge brass sheet as the base. When placing my design on the metal, I used a carbide scribe to mark my cutting lines on the metal. I used a template with ovals to make my shapes.
The scribe leaves a fine depressed line on the metal sheet. This is very difficult to see, so I use a magnifying visor when I do my piercing of the metal with the saw. When piercing the shape from the brass sheet, the metalsmith must remember the simple concepts of sawing: the blade must have 3-4 teeth on the edge of the sheet being pierced; the blade should be lubricated on the back (nontooth) side (I use BurLife); and the saw does the work, not the jeweler.
If I push the blade with pressure, it will overheat and break easily. My bench block is positioned with the flat surface up to provide the horizontal surface against which I will saw at right angles. I must remember to turn the metal, not the saw when changing direction or sawing around the oval curve that I decided to use. After piercing, I have two pieces that need to be shaped with filing.
The filing effort is made with with small jewelers files and with emory boards used by a lot of people in manicure work. As can be easily seen in this picture, a lot of work is needed to remove burs and to properly shape the ovals. Both inside and outside edges need to be filed to smooth them and to round them. Once these have been smoothed, I put them in pickle (a mild acid solution in a small crock pot) and then rinse with water and then clean the surface with a green scrubby (kitchen item). Some people will use metal scrubbers, but if you have any iron pieces on the clasp after soldering and placing in the pickle, then the piece will become copper coated.
The last item that need to be done is to add a ring to the open oval by soldering it in place, and drilling a hole in the solid oval for a jump ring.
After pickling the soldered piece and folding the solid oval to make the clasp toggle, the finished clasp is ready to be used.