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Prong diameter guide


#1

Does anyone know of a simple guide or chart or formula for what
constitutes the minimum diameter or gauge of wire when fabricating
prong settings for the various types of metals and their various
karats normally used in the industry? Any help in recommending a book
that I could buy or an organization that would be willing to supply
this would be greatly appreciated.

Thanks,
Craig Evans


#2
Does anyone know of a simple guide or chart or formula for what
constitutes the minimum diameter or gauge of wire when fabricating
prong settings for the various types of metals and their various
karats normally used in the industry? Any help in recommending a
book that I could buy or an organization that would be willing to
supply this would be greatly appreciated. 

I really don’t think you can specify an exact diameter of wire this
way. Too many factors. Not only do you have to consider the metal
type, but how it’s made (drawn wire versus cast, fabricated with
solder, which might anneal the wire, or with a laser welder, which
usually does not, and so on) And you need to consider the type of
construction of the head. If you’ve got a wire prong that’s coming
up from a well attached undergallery just below the girdle of the
stone, then the overall wire length is short and pretty sturdy
compared to a wire coming up from much farther below the girdle. And
the size of the stone is important too. As an example, in platinum,
if I were making a standard basket style head with an undergallery
just slightly smaller than the stone diameter, that the stone could
be seated right down on, in contact with the undergallery, for a
quarter carat stone, for earrings, I’d be quite comfortable using a
wire about .6 mm or even less. In short, it could be quite delicate
and still be plenty strong. Take even that same style head/setting,
but make it a two carat diamond with the undergallery for some
reason located lower down a bit, and put it on a finger ring, I might
want a prong 1.2mm or more, depending on just how long the prong had
to reach before it bent over the girdle and other factors too. While
you can suggest a minimum wire size for a prong, you pretty much need
to specify the exact item you’re making, the type of setting, and how
it will be used, the look your after, and even the type of stone to
be set, in addition to the type of metal, before you really can
decide what that minimum wire size would be.

Rather than looking for a chart, become familier with the metals and
their elasticity and strengths, and think like an engineer when
planning wire sizes for prongs. Look at the design you’re making,
and decide how much strength it will need. Remember that in many
cases, the size of the tip above the girdle is less of a factor than
the strength of the prong at and below the girdle. And keep in mind
too, that too thin a wire may be harder to set if you don’t have
enough to work with, or the metal is too springy and flexible to sit
still and behave…

Peter