You always learn more from your mistakes than your successes (or so they say)...
After all the tumult in cutting the building, I'm re-thinking cutting the turret instead. I don't have to cut the hardened steel ball. That little bit can nestle into a small depression I'll make. And cutting the aluminum plug won't be too difficult for a razor saw. And that way, I'll leave the building alone. Ideally, it's a job for a milling machine (which I really don't have) and holding onto a conical part is very tricky. I suppose I could embed it in some sculpey and then harden that to give a good support to the part while I cut it. That could work.
