but find making a neat efficient closure tricky.
Anna, locket closures ARE tricky, by hand. Easiest is to drill a hole
for the button, put a leaf spring of any metal you choose on the
button, and then rivet the spring to the base, next to the button.
Then, when you push the button it will spring back, and on that
button, on the inside, is a bit of a claw or dimple that pops into a
matching depression in the lid. Still small work and close
tolerances, but it’s a pretty typical catch, still.