Extant double spiral fibula (also called “spectacle fibula by Victorian archeologists) have been dated between the 10th to 4th centuries BC and are mainly associated with the Hallstatt and La Tene cultures. A double spiral fibula is made from a continuous length of bronze or silver wire and can range from 3.7 cm to 20.7 cm.
16 gauge copper wire (user copper rather than bronze or silver due to cost and availability)
Used the basic metal workers tools that have not changed much throughout time;
round nose pliers
Liver of Sulfur
Towards the start of the pandemic, I took an online basic.fibula class at a Viking festival event which made me want to explore historical fibula. After studying photos of extant double spiral fibula, I set out through trial and error to work out the length and gauge of wire needed to produce sturdy, usable pins. What I found that works the best is to bend the ends for the pin and latch, create the infinity loops in the middle freehand rather than using a jig, then spiral each end to the middle.
When I used a jig for the infinity, it looked contrived rather than the natural look of the extant pieces.
At this point I work harden the spirals and the pin with a jeweler's hammer on a medium size anvil. Using an anvil rather than a bench block allowed me to put the pin and latch ends in the stake holes (a hole in the anvil for putting in forming stakes) which allowed me to hammer the spiral until it was hard to bend (work hardening).
Next, flatten and bend the catch end to form the catch. Trim the pin to fit to the catch and used a fine file to bring the end of the pin into a point.
I used Liver of Sulfur to patina the copper.