How would this have been made?
Michael Koblic
Specifically the base: The description says "turned brass". In 1600, would
it have been turned from a large brass chunk? Would it have been rough-cast
first and then "cleaned up" by turning? If turned, presumably this would
have been done by hand...?
--
Michael Koblic,
Campbell River, BC
kfvo...@gmail.com
> http://www.nmm.ac.uk/collections/displayRepro.cfm?reproID=D9025&pictu...
>
> Specifically the base: The description says "turned brass". In 1600, would
> it have been turned from a large brass chunk? Would it have been rough-cast
> first and then "cleaned up" by turning? If turned, presumably this would
> have been done by hand...?
>
> --
> Michael Koblic,
> Campbell River, BC
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
Jim Wilkins
> http://www.nmm.ac.uk/collections/displayRepro.cfm?reproID=D9025&pictu...
>
> it have been turned from a large brass chunk? Would it have been rough-cast
> first and then "cleaned up" by turning? If turned, presumably this would
> have been done by hand...?
>
> --
> Michael Koblic,
> Campbell River, BC
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.
http://mitpress.mit.edu/catalog/item/?tid=7085&ttype=2
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
Stormin Mormon
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.
--
Christopher A. Young
Learn more about Jesus
www.lds.org
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"Michael Koblic" <mko...@gmail.com> wrote in message
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Michael Koblic
"Jim Wilkins" <kb1...@gmail.com> wrote in message
news:13f20a1a-01b8-4345...@k17g2000yqb.googlegroups.com...
I figured as much. All those curves...
sta...@prolynx.com
> http://www.nmm.ac.uk/collections/displayRepro.cfm?reproID=D9025&pictu...
>
> it have been turned from a large brass chunk? Would it have been rough-cast
> first and then "cleaned up" by turning? If turned, presumably this would
> have been done by hand...?
>
> --
> Michael Koblic,
> Campbell River, BC
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
Kevin(Bluey)
> http://www.nmm.ac.uk/collections/displayRepro.cfm?reproID=D9025&picture=1#content
>
>
> Specifically the base: The description says "turned brass". In 1600,
> would it have been turned from a large brass chunk? Would it have been
> rough-cast first and then "cleaned up" by turning? If turned, presumably
> this would have been done by hand...?
>
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.
--
Kevin (Bluey)
"I'm not young enough to know everything."
Paul Hovnanian P.E.
>
http://www.nmm.ac.uk/collections/displayRepro.cfm?reproID=D9025&picture=1#content
>
> Specifically the base: The description says "turned brass". In 1600, would
> it have been turned from a large brass chunk? Would it have been
> rough-cast first and then "cleaned up" by turning? If turned, presumably
> this would have been done by hand...?
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.
--
Paul Hovnanian pa...@hovnanian.com
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