Q: How do you go about making a tapered tube, like the spout for
an oil-can or teapot, in silver sheet?
A: The shape you're talking about is now commonly called (at least
in metalworking circles) a Spiculum. And they're not hard to make. A tapered
blank of sheet metal is hammered, with a cross-peen hammer, into a v-shaped
groove in a piece of wood, till you've curved it around to about a semicircular
arc, about halfway closed. Then you close up the arc the rest of the way
by hammering from the outside, working it around and the edges together,
which are then soldered.
Keeping the developing form in the groove will keep it from collapsing
flat while you hammer, as will watching what's happening, and working down
any areas that are bending and/or creasing more sharply than the rest. The
tapered shape makes it much easier to close uniformly than a straight tube
is, which tends like the dickins to flatten when you don't want it to. Also,
the taper, if you've made the thing from any decently thick metal, will
allow you to bend the finished form to gentle curves much more easily and
with less distortion than a straight sided tube would do.
Several books discuss the process, which is commonly taught as a fairly
basic excercise in college metals classes. In particular, "Form Emphasis
for Metalsmiths", a by now classic work by Heikii Seppa. It was this
book and author which either coined or popularized the term spiculum, I
believe, as well as the term anticlasic raising, another type of complex
form development.
Peter Rowe
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