Locking Meckanism

This is question to everyone,
I have a job to repair a locket that’s made out of what looks
like a Mexican Coin. There is an Aztec calendar on front and
back with a single circle of rose cut diamonds bead set towards
the edge. The coin is about the size of a silver dollar. The
calendar on one side opens to like a pocket watch to disclose a
picture. The customer brought it to us because another jeweler
failed to lead solder to case permanently closed and burnt the
picture of her grandfather. I’ve managed to rebuild the locket
and remove the lead solder but, the lead solder flux has eaten up
the springs in the catch. Also the catch is one I never seen
before.

Question #1 Has anyone read any books on watch & locket complex
closing mechanism?

Question #2 Has anyone ever worked on this type of locket? I
think this locket is an antique so it’s unlikely one of us made
it. Jim alpine@hay.net

I have a job to repair a locket that’s made out of what looks like a Mexican
Coin.
I’ve managed to rebuild the locket and remove the lead solder but, the lead
solder flux has eaten up the springs in the catch. Also the catch is one I
never seen before.

Hi Jim,

Difficult to tell. Is the spring really in the catch? Usually it
is built in to the hinge or under it. If the hinge consists of
an even number of pieces (4 or 6 tubes), there could have been a
torsion spring inserted instead of the hinge pin. This would be
made of two pieces of flat hardened spring steel with an
elongated-oval cross-section, running the whole length of the
hinge. They are inserted with the lid closed, and at one end, a
silver wedge is pushed in tightly to lock them in place. The
other end of the springs is wrapped in a bit of binding wire and
twisted with a hand vise until the desired tension is reached.
Another wedge is forced in at this end of the hinge. Unlocking
the catch the lid should - well, spring open. The wedge material
should be work hardened or one could use nickel silver.

Of the othe kind of spring which is fastened under the hinge, I
don’t know much, perhaps you could look at a pocket-watch.

Regards, Markus