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JohnHarbeck
05-01-2013, 11:36 AM
The thread on metric reminded me of another pet peeve.
Is there a logical explanation for the various 'gauge' names for metal sheet.
One reference shows 16 gauge = 0.0598 for uncoated steel sheet, 0.0635 for galvanize coated [but how thick is the galv coating -- in the steel mill it's speced in grams per square meter separately for each side of the steel?] and 0.0508 for aluminum.
We won't even look at copper, brass sheet or electrical wire sizes for now.
I worked for 40 years in a steel mill on the xray gauges that were the 'feedback' on rolling mills that controlled the final thickness of the sheets & plates.
In all that time I NEVER saw a thickness gauge, manual or computer, set up by a gauge number, only in DECIMAL thickness.
Guess that's why I have a bookshelf of Machinery's Handbooks and supplier catalogs!

John in NW Indiana

Black_Moons
05-01-2013, 11:45 AM
One reference shows 16 gauge = 0.0598 for uncoated steel sheet, 0.0635 for galvanize coated [but how thick is the galv coatring?] and 0.0508 for aluminum.
John in NW Indiana

I don't know myself, But that has always buged me too. I can almost understand the extra size for galvanized because its weaker surface coating and you would want '16ga of steel', but why the heck is aluminum thinner??

sasquatch
05-01-2013, 06:02 PM
Interesting question John, looking to see the responses to this question.

TRX
05-01-2013, 07:55 PM
Up through the early 20th century, every industry had its own gauge system. And they were usually different for different metals - 20 gauge brass was a different thickness than 20 gauge iron, for example.

Most of them originated in Britain at the dawn of the Industrial Revolution, when "standard" meant "whatever Nigel has been doing lately."

SGW
05-01-2013, 08:56 PM
Basically, each company invented their own standards. Thus you have the Washburn & Moen wire gauge, the Stubbs wire gauge, etc. Likewise, the Morse Twist Drill Company invented Morse tapers, Brown & Sharpe invented B&S tapers, and so on. Industry-wide standards hadn't been conceived of yet. Eventually, smaller companies dropped out, or chose to adopt the standards used by the dominant companies in the various industries, so today we are left with the survivors, and virtually none of the gauges make any logical sense. They are just what various companies came up with back in 1875, or whenever it might have been.

topct
05-01-2013, 09:21 PM
The gauge for aluminum is it's actual thickness. It was at Kaiser anyways.

darryl
05-02-2013, 12:07 AM
The only thing 'gauge' does for me is test my memory- see if I can remember how thick that is in thou-

I wonder how they talk about it in sheet metal shops- somebody says 'hey, help me with this sheet of 16 gauge', or do they say 'help me with this sheet of oh five nine'

Black_Moons
05-02-2013, 01:36 AM
The only thing 'gauge' does for me is test my memory- see if I can remember how thick that is in thou-

I wonder how they talk about it in sheet metal shops- somebody says 'hey, help me with this sheet of 16 gauge', or do they say 'help me with this sheet of oh five nine'

The metal shop I went to had it in decimal till about 0.041" iirc? And then went to gauge (for 8 to 14ga or so, then went to fractional inches)

Lew Hartswick
05-02-2013, 08:38 AM
This thread brings up a pertinent thing to a project at school. The material in
question is hot rolled steel. Dwg. calls 1/8" but the only things I can find in
the stock measures either 0.130 or a bit over 0.100" (varies from about .105
to .115 ) So what gauge are they? Making something out of this plays the
vary devil with trying to maintain tolerances on other parts. :-(
...lew...

TriHonu
05-03-2013, 12:40 PM
Here are a few pieces of the answer:

The legal definition of Sheet Steel Gauges is from 15 USC 206 (http://www.law.cornell.edu/uscode/text/15/206) - Standard gauge for sheet and plate iron and steel.

Some history of how we got to the current gauge sizes and thicknesses can be read from Steel Market Update Manufacturers Standard Gauge History (http://www.steelmarketupdate.com/modules/pages/content/index.cfm?pageId=36).

A list of the Manufactures Standard Gauge thicknesses can be viewed HERE (http://www.scsenergy.com/scsdatagage.htm)

Jaakko Fagerlund
05-03-2013, 02:10 PM
And if you really want to do something easily, just use decimals and ditch the gauges (applies to all gauge systems).

Stu
05-03-2013, 02:24 PM
In all the metal shops I worked steel went by gauge , aluminum by thickness .025 .032 .040 and so on and copper by oz. per sq. ft. with 16oz. the most common. At the time it never seemed odd.

Stu

Juergenwt
05-03-2013, 04:01 PM
The thread on metric reminded me of another pet peeve.
Is there a logical explanation for the various 'gauge' names for metal sheet.
One reference shows 16 gauge = 0.0598 for uncoated steel sheet, 0.0635 for galvanize coated [but how thick is the galv coating -- in the steel mill it's speced in grams per square meter separately for each side of the steel?] and 0.0508 for aluminum.
We won't even look at copper, brass sheet or electrical wire sizes for now.
I worked for 40 years in a steel mill on the xray gauges that were the 'feedback' on rolling mills that controlled the final thickness of the sheets & plates.
In all that time I NEVER saw a thickness gauge, manual or computer, set up by a gauge number, only in DECIMAL thickness.
Guess that's why I have a bookshelf of Machinery's Handbooks and supplier catalogs!

John in NW Indiana

John - let's see what the defenders of the good old imperial system system have to say on this.
So let's hear from you and how you defend the use of all these gauges. After all it is rooted in our industry for generations. How much superior is this to calling for a 3mm sheet of plastic, steel, copper etc. etc..

kf1002002
05-03-2013, 05:00 PM
My understanding is that in the early days gauge was defined by the number of passes through the mill that it took to produce it. Thus the more passes the larger the gauge number and the thinner the steel. Of course the setup of the mill would influence this and it would be different from one manufacturer to another.

This gauge number is now probably maintained just to confuse people and to execise apprentices.



Ken

Lew Hartswick
05-03-2013, 10:08 PM
Here are a few pieces of the answer:

The legal definition of Sheet Steel Gauges is from 15 USC 206 (http://www.law.cornell.edu/uscode/text/15/206) - Standard gauge for sheet and plate iron and steel. (http://www.scsenergy.com/scsdatagage.htm)
A whole lot of good that does without tolerances. :-( So my 0.130" is "Probably " 1/8" but sure is more than a bit oversize. You'd think the bean counters would insist the tolerances would be on the thin side. :-)
...lew...

TriHonu
05-04-2013, 04:18 PM
A whole lot of good that does without tolerances. :-( So my 0.130" is "Probably " 1/8" but sure is more than a bit oversize. You'd think the bean counters would insist the tolerances would be on the thin side. :-)
...lew...

The legal definition was "...used in determining duties and taxes levied..." by the government. I don't think they cared about the manufacturing implications.

If you look at the Manufactures Standard Gauges (http://www.scsenergy.com/scsdatagage.htm) it is likely 10 gauge that is .0045 undersize...

rohart
05-04-2013, 04:58 PM
As well as all this gauge stuff, I get annoyed when something is quoted as 25mm, when they really mean 25 sq mm, or 25 mm2.

They other day I was trying to compare the three sizes of Tig welded torch feed cable, before realising I was reading too much into the quoted measurements. Did they mean 2.5mm ID, or was 25mm the minimum bend radius, or what ?

There's nothing you can do about it, though. Just have to stick conversion charts all over the shop walls.

J Tiers
05-04-2013, 05:57 PM
And if you really want to do something easily, just use decimals and ditch the gauges (applies to all gauge systems).

Clearly the best and only solution.

uute
05-04-2013, 06:48 PM
[QUOTE=TriHonu;848813]Here are a few pieces of the answer:

Some history of how we got to the current gauge sizes and thicknesses can be read from Steel Market Update Manufacturers Standard Gauge History (http://www.steelmarketupdate.com/modules/pages/content/index.cfm?pageId=36).

""WELL, THere's your PROblem!!!"" Congress fixed it! :D :D :D

darryl
05-04-2013, 07:38 PM
So, no unsurprisingly, the whole thing was about the government picking yet another thing to tax us on. No wonder it was made confusing-

cameron
05-05-2013, 06:35 AM
John - let's see what the defenders of the good old imperial system system have to say on this.
So let's hear from you and how you defend the use of all these gauges. After all it is rooted in our industry for generations. How much superior is this to calling for a 3mm sheet of plastic, steel, copper etc. etc..

It's not superior, it's essentially the same. Calling for a 3mm sheet is meaningless without a stated or implied tolerance. Gauge standards carry their own tolerances.

Jaakko Fagerlund
05-05-2013, 02:04 PM
It's not superior, it's essentially the same. Calling for a 3mm sheet is meaningless without a stated or implied tolerance. Gauge standards carry their own tolerances.
Base line thickness and tolerance is two different things. In actual reality there is such a thing as universal shop tolerances, it even has a nice ISO standard. Unless print says otherwise, the universal tolerances apply.

As for sheet metal tolerances, it is up to the manufacturer or buyer to decide acceptable tolerances, but if I go and get 3 mm sheet, I get a sheet that is at least 3 mm thick and probably only a few hundreds thicker.

cameron
05-05-2013, 02:33 PM
Base line thickness and tolerance is two different things. In actual reality there is such a thing as universal shop tolerances, it even has a nice ISO standard. Unless print says otherwise, the universal tolerances apply.

As for sheet metal tolerances, it is up to the manufacturer or buyer to decide acceptable tolerances, but if I go and get 3 mm sheet, I get a sheet that is at least 3 mm thick and probably only a few hundreds thicker.

Your "nice" ISO standards were set for you in Brussels. Imperial and other inch/pound/second standards were mostly set in the U.S. or Britain. I guess that makes them not so "nice".

Jaakko Fagerlund
05-05-2013, 11:53 PM
Your "nice" ISO standards were set for you in Brussels. Imperial and other inch/pound/second standards were mostly set in the U.S. or Britain. I guess that makes them not so "nice".
The **** is your problem exactly?