I think the best solution would be to build a bezel cup for the
coin and attach it to the clip by means of a rivet. After that, set
the coin as usual.
Bob: Having worked with titanium, and the other refractive metals, for
many years, I can tell you that welding or soldering will not be a
practical option. Welding requires an oxide free surface, and the
oxide is what gives titanium its color and hard surface. Normally,
any oxide is removed chemically with hydrofluoric and nitric acid,
and the weld is done in a gas-shielded environment, using argon gas.
This is fine for government contractors, but not practical in the
A mechanical joint, like a rivet, screw, tab, etc., is the only way