So the consensus opinion here and on the Facebook page is that annealing the brass is the cure for most of my ills.
I really should have thought of that. You may remember when I mentioned that the difference in stiffness between the modern wire and the 16th century wire for pinmaking was the result of work-hardening because of the way that their wire was drawn as it compares to the modern methods of wire drawing. The folding of the metal in the 16th century style combined with the effort involved in forcing it through the die stiffened the crystalline structure of the metal.
Caple says that in order to wrap the heads, they had to anneal the wire first because the stuff didn't bend.
It's much the same problem with modern brass sheets. Brass, like all sheet metal, is rolled out to the desired thickness in a machine press that compresses the brass between massive wheels. This has the same effect as drawing wire through a period die.
In my sheets of brass, the crystalline structure is aligned and as stiff as it gets. In order to get more play in the metal, I need to excite the molecules by heating the brass and mess up that crystalline structure once more before it will ever suffer the hammer. It's much the same as doing anything with iron.
The plan for today is to go out and get a thicker piece of brass and then heat it to a dull red heat using a propane torch and work it from there. I have high, cautious, hopes.
Thanks to the Wayne at Leatherworking Reverend, Louise Pass of Woodsholme, and Andrew Williamson for their advice on this. I'll let you know how it goes!
Sidenote: Because it's been so long since I was in high school metal shop, I looked it up online to make sure there wasn't anything I've forgotten. All of the sites and videos on brass annealing are dedicated to the community of people who reload rifle shells.
I suppose it's the same thing, except my thimble won't explode if I do it wrong...
"So Sybil says to Marjorie, 'Well we didn't want you to come to the quilting bee any way!' and you know how Marjorie gets. She says 'I'll come to that quilting bee if I..."
(Fade to black)
(Voiceover) Has this happened to you? Are you the victim of an reloaded thimble? Call Calvin & Hobbes, attorneys at law...