On Nov 30, 10:54 pm, Sylvia Else wrote:
The obvious answer is that you bend the metal of the connector so that
it holds the wire in place.

This doesn't seem very satisfactory. Metal always retains some
flexibility, even when bent beyond its yield point. No matter how hard
you squeeze, there'll be some rebound when you release the pressure,
which should result in a loose joint.

After having had a bad experience trying to crip a lug some years ago, I
recently faced the need to do this again. So I bought a moderately
expensive ratchet based crimping tool. And, rather to my surprise, it
actually works.

But that doesn't answer the question of how.

Sylvia.

The ratchet tool provides substantial mechanical advantage compared to
many of the cheap tools, and therefore enormous pressure on the
joint. With the right tool, the joint is squashed down by the exact
amount, whereas cheap hand tools are more "hit and miss" as to whether
you have applied the right pressure to them. the "die" is also a lot
better on ones that I have seen, and probably designed to put the
pressure in the exact right places at the right time during the crimp.
(ie, more efficient use of the energy you apply with your hands)

As the metal parts of the surface being crimped are squashed really
hard by the tool, they probably heat up (compression causes heat, and
metals expand with heat,), and then shrink as they cool, tightening on
the wire ?.