How would this have been made?

Cast then cleaned up on a lathe.You could spin it in parts then soldier it together but that's way more trouble in my opinion. Karl

Holzapffel's "Hand or Simple Turning", page 17, shows a woodcut from

1568 of a man turning a large sphere on a pole lathe. He is holding the chisel under his arm in the way I've seen recommended for turning metal by hand.

I think the base might have been cast in an open sand mold formed by rotating a template of the shape. Fill it, wait a bit, pour it back out leaving a thin shell of solidified metal.

" Pyrotechnia" is a thorough description of smelting, refining and casting practice from 1540. The author made bells and cannon, not small artsy stuff, and as the title suggests he concentrates on work done with fire rather than tools, though some tool work necessarily crept in.

When I was 5 years old we lived near a small foundry. They let me watch as they mostly hand-shaped the sand molds for parts to fix old looms and cast them in aluminum. The tools are similar to those for wax carving.

jsw

Just off the top of my head, probably cast (lost wax method?) and then turned. Water wheel for power, or horse or oxen walking around an axle.

Still, some seriously incredible quality work for that time era. Would have to be expensive, for sure.

I figured as much. All those curves...

Probably done via lost wax like bells. For something like that, they probably would have made a wooden pattern on a simple pole or treadle lathe, cast a plaster mold to get the reverse, then made wax patterns from that. Chase with hand tools afterwards, that's what apprentices were for. Engineering lathes as we know them weren't around until MUCH later and probably wouldn't have been used on such anyway, they could get a decent finish without them.

De Re Metallica has a lot on old-time processes. A lot of techniques were simply not written down, either, were part of guild "lore" and were only passed on master to apprentice.

Stan

Possibly spun from brass sheet on a metal spinning lathe.The base and post at least were probably done by this method.

Wooden forms are made and mounted in the lathe and the brass is worked and formed over the form by spinning the form and the brass sheet , tools are used to shape and form the brass into the forms.

It's an old trade and is almost a lost art ,although there are quite a few home shop metal spinners around.

Just guessing here: Turning (anything) during the 17th century was probably done either by human or water power. Steam power wasn't quite there yet. So, considering that the power needed to turn down a 'large chunk' was relatively scarce, I'd say rough cast first, then turned.