As far as I’m aware, the traditional method is to work harden it by
I’ve found it best to make the pin about 10mm longer than required
and bend the unwanted end at right angles to make a long “L” shape.
You then hold the “good” end securely and, with the short “L” in
pliers, twist the pin one or two complete turns. Test its springiness
by “pinging” it and twist more if required. You can then cut the
unwanted bit off and file the work hardened pin to shape.
There is a nice little benefit from the twisting because it leaves a
rather attractive shallow barley sugar look to the pin, which also
makes it slightly more resistant to sliding out should the clasp
come undone. Of course, if you don’t like the barley twist look you
can always file it smooth - its very shallow.
Regards, Gary Wooding