On Friday, July 21, 2017 at 2:59:05 PM UTC-7, Bob La Londe wrote:

This is a pretty typical lead casting (sinkers, jigs, spinnerbaits, etc)
mold. The hinge shown works pretty darn well. It moves easily, and does a
good job of helping to hold the mold halves in alignment at the hinge end.
The opening (handle side) end has two alignment pins with radius ends

There's some options with extra parts (mainly, though, I don't like loose
parts...). In particular, your alignment pins could go through the
mold and a wedge can snug the halves together. On a lathe, it's
only gonna take a bit of a head on the protruding pin end, that engages
an external wedge of the sloped-metal-with-keyhole type.

With a CNC setup, the wedge can be simpler, if you slot the pin, but
that might eventually score the mold. Internal wedge (like for Morse taper
release) also needs a radius'ed edge;