Draft FAQ on gage/gauge
James Kirkpatrick
corrections, and suggestions:
86. What does "gage" (or "gauge") mean?
Webster's seems to prefer "gauge", but Machinery's Ready Reference
uses "gage" for sheet, and "gauge" for wire. Strictly speaking,
"gauge" is a measuring device, and "gage" a measurement system,
but common usage has corrupted the distinction.
An arbitrary assignment of numbers to size, used on sheet, wire,
and many other things (tubing, shotgun bore, needles, and so on).
Unfortunately there are so many different standards that using gage
to specify a material is almost useless, and perhaps even dangerous.
If in doubt, use decimals.
For example, in U.S. gage, the standard for sheet metal is based
on the weight of the metal, not on the thickness. 16-gage is listed
as approximately .0625 inch thick, and 40 ounces per square foot
(the original standard was based on wrought iron at .2778 pounds per
cubic inch; steel has almost entirely superseded wrought iron for
sheet use, at .2833 pounds per cubic inch). Smaller numbers refer
to greater thickness. There is no formula for converting gage to
thickness or weight.
Wire might be specified in American or Browne & Sharpe, Birmingham or
Stubs, Washburn & Moen, Trenton Iron Co., Stubs' Steel, Imperial Wire
gage, music wire gauge, or others. In the US, I've commonly seen
electrical wire in AWG (American Wire Gauge); even-numbered values
are much more common than odd ones. As an example, 12-gauge wire
is .081" (AWG), .109" (Birmingham or Stubs), .105" (Washburn & Moen),
.028" (music wire gauge). In most cases a larger gauge means smaller
wire, except music wire goes the other way around!
On September 20, 1994, Rowland Carson posted a nice list of most of
the gauge systems in use worldwide:
Alhoff & Muller Music Wire Gauge music wire
American Screw & Wire Co Music Wire Gauge music wire, spring wire
American Zinc Gauge zinc sheet
ASA B32.1 uncoated thin flat metals USA
Birmingham Gauge BG iron hoop & strip, steel sheet
Birmingham Wire Gauge BWG iron & steel telephone wire
Birmingham Wire Gauge for Silver & Gold silver & gold
Brown & Sharpe Wire Gauge B & S non-ferrous sheet & strip
Brunton Music Wire Gauge music wire
Card Wire Gauge CWG fibre yarns
Continental Zinc Gauge sheet & strip
English Music Wire Gauge music wire
English Zinc Wire Gauge zinc sheet
Felten & Guilleame Music Wire Gauge music wire
German Sheet Gauge sheet metal
Instrument Wire Gauge instrument wire
ISO Metric Preferred Series (R388) all applications
Junge de Paris copper wires
Lancashire Pinion Wire Gauge LPG cast steel drill rods
Mathieson & Hegeler Gauge M & H zinc sheet
Millimetre Wire Gauge steel wire
National Wire Gauge NWG steel wire
Poehlimann Music Wire Gauge music wire
Printers Wire Gauge printers wire
Roebling Wire Gauge steel wire
Sewing & Darning Needle Series sewing & darning needles
Standard Wire Gauge SWG wire & strip, tube thickness
Stitching Wire Gauge
Stubs Iron WIre Gauge iron wire
Stubs Steel Wire Gauge steel drill rod
Tinplate finished tinplate
Twist Drill & Steel Wire Gauge drill rod
US Galvanised Sheet Gauge GSG galvanised sheet
US Manaufacturers' Standard Gauge MSG iron & steel sheets & plates
US Standard Gauge USG stainless steel
US Steel Wire Gauge USSWG steel wire
Washburn & Moen Gauge WG steel wire
Warrington Wire Gauge steel wire
Yorkshire Wire Gauge steel wire