At one point in my travels, I spent a couple of years in Lima, OH.
Best known as the home of the Lima Locomotive works. They made some
of the biggest (and best, just ask them) steam engines ever made.
(Now they make tanks for the army. Go figure.) (Which explains why I
can list “Unindicted Tanknapper” on my resume.) (Looooooong story,
that.) (I didn’t actually boost a tank, I just helped “acquire” one
for the local museum.)
Anyway, one of the ways they did (and still do) get the steel tires
onto loco wheels is to use a giant round “ring of blowtorches” to
heat the bejesus out of the tire to expand it enough to slip onto
the wheel. The tires are still shrunk on like that, even on modern
diesels. What’s even funnier about it is that it’s a trick they
picked up from horse wagon wheel makers. All those steel rims on
buggy wheels? They’re shrunk into place on the wood. The pressure
helps hold the spokes in place, and keeps the whole thing from
Meanwhile, Peter: Yes, I think the Canadian cored coins are.
effectively shrunk into place. I think I remember hearing that the
central section goes in undersized, but blank, and part of the
coining operation slams it hard enough to force it to expand to lock
into the brass ring. Same mechanical effect, but different way to
get there, and the tolerances aren’t quite as fussy. (It’s basically
a giant flush rivet at that stage.)
You want real fun, my understanding of the way they do the
nickel/copper/nickel sandwich sheet that US quarters are made out of
is explosive welding.
Dig a 4x8 foot pit. Put a thick steel plate at the bottom of it. Put
the nickel/copper/nickel sandwich on the plate, and then put a sheet
of C4 explosive across the top. Fill pit with water, (as a tamper)
and then fire the C4. Presto Boomo! Instant giant sheet of not-quite
On the scary side, I’ve got a book on numismatic forgery that shows
a guy who modified a 12ga shotgun into a die press. Loaded up custom
shells with one side of the coin die as the 'bullet’and then fired
it into a female die-holder welded across the muzzle. (For anybody
reading this DO NOT, FOR THE LOVE OF GHU, EVEN THINK OF TRYING
THIS YOURSELF. It’s so spectacularly dangerous (stupid) even I
wouldn’t think of it.) I mention it as an example of just how far
out there people can get.
As far as doing it on jewelry scale things, it is possible. The
longer an area you have in contact, the stronger a joint will be.
For example: a piece of wire at right angles through a piece of
.75mm sheet wouldn’t be all that strong, as there’s only that one
.75mm thick contact area. But a wire grabbed in the long axis of a
tube, or set deeply into a thicker block, so the contact area is a
length of the wire 2-3-4mm long, that’d have a lot more strength.