Gauge/Gage - definitions to confuse you

[Visorblue]

I was telling a friend that I'm learning to weld and the discussion got to the meaning of gauge, like 10 gauge - 0.1345" thickness. He related it to shotguns and said, "I think the idea has something to do with how many of something will fit in a standard container. So if 20 of them fit in the container, they’re one size, but if only 10 fit in there, they’re a lot bigger."

Seemed logical for shotguns but not sheet metal so I decided to look it up online -- changing my spelling to "gage" as a result. Then I got really confused:

"Dictionaries (at least in the US) seem to consider "gage" to be an alternate spelling of "gauge". But common usage suggests "gage" refers to sheet metal thickness, gage blocks, and most concrete measurement systems and devices. "Gauge" seems to refer to pressure gauges and level gauges. Comparing Machinery's Ready Reference, Machinery's Handbook, and the MSC catalog, there is no agreement on "wire gage" versus "wire gauge". Time seems to have corrupted any clear distinction, and things are most likely different in England and other places.

So my particular preference is to only use "gauge" for devices that measure more abstract things like pressure and level.

Gage: 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square foot (the original standard was based on wrought iron at .2778 pounds per cubic inch; steel has almost entirely superseded wrought iron for sheet use, at .2833 pounds per cubic inch).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."

These "definitions" are more confusing:

1. “Gauge refers to the thickness of either the pipe wall for both chainlink and ornamental fences or the thickness of the wire for chainlink mesh. The thicker the pipe or wire wall, the smaller the gauge. For example, 16 gauge pipe is thicker than 17 gauge and 9 gauge wire is thicker than 11 gauge.

In reality, when talking about chain link mesh, GAUGE MEANS NOTHING! Why? Because what is 11 gauge chainlink mesh to one company, may not be the same to another. And, it seems that every year the wire gets thinner but the gauge remains the same.”

2. “Gauge measures the thickness of the shrink film. A higher gauge number would correspond to a thicker film.”

This one was more helpful:

"Sheet metal thickness gages are based on a weight of 41.82 pounds per square foot per inch of thickness. This is known as the Manufacturers' Standard Gage for Sheet Steel, and is primarily used for sheet steel. For materials such as Aluminum and Brass the thicknesses will be different. Thus a 10 gage steel sheet which has a thickness of 0.1345 inch will weigh 41.82*0.1345 = 5.625 pounds per square foot."

http://www.efunda.com/designstandard...et_forward.cfm

If you have a better definition, please let me know. Thanks.

[Rick Moran]

A lot of the stuff you read pertaining to weight of steel and other materials are really important to an engineer who has to consider structural strength when designing something. And, maybe even to a metal contractor or shipper who has to move the product or buys in bulk. But for everyday use, most shops or business' go buy the standards.

Lower gauge numbers are thicker when dealing with wire, drills or sheet metal sizing.
ie: 16ga. is thicker than 24ga. steel, #10 wire is thicker than #16, and a # 11 drill is thicker than a #200.

The opposite applies to screw sizes.
ie: #10 screw is thicker than a #8.

I believe that's true for shotgun gauge.

Experience has trained me not to trust anything of importance that is "marked or labeled" w/o verifiing it with my micrometer or calipers.

[Berniep]

Ok so I still don't get where the "16" in 16 gage sheet metal came from
16 what?
Would 16 41.82 pound, one square foot in dimension stacked on top of one another be 1 inch thick?
Shotguns are based on the number of balls of bore diameter that can be made from a pound of lead.

Aahhh who needs decimals anyway.

[TEK]

[QUOTE=BerniepShotguns are based on the number of balls of bore diameter that can be made from a pound of lead./QUOTE]

Correct. A twelve gauge bore diameter would be the same as a round ball of lead weighing one 12th of a pound(.629).......A 4 gauge shotgun(yep, they made 'em) will have a bore dia. equal to a 1/4 pound lead ball.(ouch!)

[billie_]

The earliest standard for sheet metal gauges actually ran the
other way. This is the American Institute of Mining Engineers Standard
Decimal Gauge, from 1877. The gauge number was the thickness
of the sheet in thousandths of an inch. The series ran from
2 to 22 by 2's, 25, 28 to 40 by 4's, 40 to 100 by 5's, 110 to
180 by 15's, and 200, 220, 240, 250.

The gauges that you're more familiar with began with the "US Standard
Gauge" for tax-levying purposes in 1893. They defined the mass
of a cubic foot of wrought iron to be 480 lb. A 1 foot by
1 foot by 1/2" sheet would weigh 20 pounds, or 320 ounces, and
the gauge for sheet steel weight 320 ounces per square foot was
defined at 7/0. From #7/0 to #0, the sequence went down by
20 ounces, 320, 300, ..., 180. Then from #0 to #14 it went down
by ten ounces; from #14 to #16 by five ounces; from #16 to #20
by four ounces; from #20 to #26 by two ounces, from #26 to #31,
ounc ounce, from #31 to #36, by half an ounce, and from
#36 to #38, a quarter of an ounce. In this scheme, assuming
that 480 lb is the weight of a cubic foot of sheet metal, #16
is 1/16" an inch - a nice round number. But no, life couldn't
be that simple!

The US standard gauge wasn't very useful, because most sheet metal
was rolled steel, not wrought iron, and rolled steel weighed closer
to 502 pounds per square foot. It was never clear whether steel was
being sold/taxed by thickness or by weight per square foot.

After two years of confusion, the American Railway Master Mechanics
Association called for a return to the decimal gauge. Since then,
the decimal gauge has often been called the "Master Mechanics Gage".

Despite this plea, most of the manufacturs continued to use a variant
of the US standard gauge, interpreted by weight and not by thickness.
This is called the "Manufacturer's Standard Gauge", and is the one
in common use in the US for sheet steel. This is why #16, which
was originally 1/16"=0.0625" thick in the US Standard gauge, is actually
480/502 this thickness, or 0.0598".

Aluminum, copper, magnesium, and zinc are measured in completely
different gauge(s) and have stories of their own!


this was a cut and paste from internet..hope it helps

[zapster]

i have diffrent size guages in the dashboard of my truck

tach...
oil pressure..
water temp..
and turbo boost...
and a bunch of others..



...zap!

[ElectroLight]

Visorblue,
Thanks for starting this thread, I had too questions about "guage" I just didn't know how many questions until reading this!

Billie_,
Comprehensive sheet metal guage explanation! Now I know why digital caliper reads 0.0598" on my 16 guage stock!

BTW, another stellar post by zap... very helpful.

[zapster]

BTW, another stellar post by zap... very helpful.

lighten up will you?..
its all in fun..or dont you know what that is?

...zap!

[zapster]

there is a very detailed thickness/guage chart in "mig tig and oxy fuel welding welding" forum..

first "stickey" post F.Y.I.

...zap!

[spuddown]

Originally Posted by ElectroLight

BTW, another stellar post by zap... very helpful.

I see you were lurking too.

[Sandy]

i have diffrent size guages in the dashboard of my truck

One of those is the oil guage. If the pointy thing is way to the right, someone put regular oil in the engine. If it's way to the left, someone put "no oil" in there.