Gauge - new query

Jewelry Discussion
1

Jess4203@aol.com said Regarding the Brown and Sharp gage of
metals, you are the physicist, but I would assume that they are
linear. It’s just that bigger gages are smaller and I guess they
start somewhere at some constant value. web page with conversion
data: http://www.kitco.com/chart.ga2mm.html No Jess4203 it is not
a linear progression, rather an extrapolation. Shlomit used
excel to solve for a conversion equation by using chart. One must
use the natural logarithm function because the numbers aren’t
linear. Originally gauge numbers referred to the number of lead
balls of the gun barrel diameter in a pound. So Kiddies, todays
question is: how did B&S decide on what number assignation to
give to the wires? A pound of copper stretched 2 feet became 2
gauge? Ideas? Why do we have different gauges for various
metals & alloys? Do Americans just have to do things
differently?

Here’s more info: The American, or Brown and Sharpe, gauge
applies to electrical copper and aluminum wire and certain alloy
wires. It ranges from No. 0000 = 0.460 inch (1.168 centimeters)
to No. 40 = 0.0031 inch (0.0079 centimeter) diameter. The
Birmingham wire gauge, used for iron, steel, and brass wires,
starts with No. 0000 = 0.454 inch (1.153 centimeters) and goes
down to No. 36 = 0.004 inch (0.010 centimeter) diameter. The
United States Steel Wire Gauge (U.S.S.W.G.) goes from No. 0000000
= 0.490 inch (1.245 centimeters) to No. 50 = 0.0044 inch (0.0112
centimeter) diameter. Cogitatively, Kat

2 
 The Birmingham wire gauge, used for iron, steel, and brass
wires, starts with No. 0000 = 0.454 inch (1.153 centimeters)
and goes down to No. 36 = 0.004 inch (0.010 centimeter)
diameter.

Hi Kat,

Citing from Turning & Mechanical Manipulation, by Charles
Holtzapffel, London 1847: “It should be further observed that
the Birmingham and other gages seem to have been originated in
great measure accidentally, or almost by the eye alone, and
without any attempt at system, either regards the values of the
intervals between the successive measures or numbers, or their
correspondence with the subdivisions of the inch.”

regards, Markus