Re: Threads

[bearbvd@domain.elided (Greg Hermann)]

At 10:48 AM 11/13/99, JHertzman@domain.elided wrote:
>While commenting on the SAE being formally an international organization,
>r.m.bies wrote "The bolts bearing this designation are not metric, not
>whitworth, but in standard inches (fractional -- fine thread)".
>
>I'm not sure when it happened, but the standard for "bolts bearing this
>designation" was long ago subsumed into the ANSI (American National Standards
>Institute) standards, apparently in at least two stages- the ASA (American
>Standards Association) in 1941 for part of it and ANSI in 1952 and 1955, as
>UNF. SAE has many standards (including grade markings for bolts, along with
>those of the ASTM), but the only "S.A.E. Standard Threads" I found are the
>ones for spark plugs, which are indeed metric and not 'inch'- in four sizes.
>The term "SAE threads" will undoubtedly survive in common use, as will
>"Whitworth" - - which isn't whitworth any more either.
>
>The ANSI standards also embrace metric bolts, but in a series which does not
>quite match those used on Alfas, which are - what? DIN?
>
>Sigh,
>
>John H.

I believe that there is an Italian standards organization which developed
the thread standards used on the older Alfas. DIN is distinctly German in
flavor--something along the lines of "Deutsch Industrie Normale".

The original Italian standards organization has probably long since been
merged into the ISO--which, at least as far as most of the seriously
competent engineering folks I am acquainted with are concerned, would
probably be best improved by setting off a tactical nuke in the middle of
its HQ!!

ISO has become a den of bureaucratic fools who have absolutely ruined the
logic of the original metric system, among other useless endeavors! They
seeem to exist mostly for the purpose of inventing some new, illogical unit
to name after whoever happens to be the political favorite of the moment!

ANSI is essentially an umbrella organization which sanctions standards
committees which are formed by the various engineering societies in the
USA, and then promulgates and publishes said standards for all and sundry
interested parties. Member organizations of ANSI would include SAE, ASCE,
ASME, ASHRAE, ISA, ACI, AISC, etc. Usually, if you get into the full level
of detail of the name of a standard, you will find something like
"ANSI-ASHRAE Standard #15-1978" This particular one happens to be the 1978
revision of the mechanical refrigeration safety standard (ASHRAE #15) .

ANSI standards are NOT codes--they are what is known as "consensus
standards"--that is to say they are developed by a consensus of a committee
made up  of people recognized as being knowegeable in the subject industry.

The standard for fine threads was definitely developed by SAE, and they are
most likely still responsible for updating it under the ANSI umbrella,
although this MAY have changed at some point.

SAE is a unique animal is some respects, because it has written standards
for some things (steel alloys come to mind) which are a dead parallel for
similar standards developed by others.

For the curious, a table of some of the Alphabet Soup above:

ASCE= American Society of Civil Engrs.
ASME= American Society of Mech.anical Engineering
ASHRAE= American Society of Heating, Refrigeration, and Air-conditioning
Engineers
ISA= Instrument Society of America (formerly Am. Soc. of Instrument Engineers)
ACI = American Concrete Institute
AISC = American Institute of Steel Construction

Regards, Greg

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