[time-nuts] time-nuts Digest, Vol 89, Issue 51

Don Latham djl at montana.com
Thu Dec 15 13:15:58 EST 2011

What I find interesting is that the first push for standardization, at
least for machine threads, came from the manufacture of arms, the
Springfield Armory, at the time of the Civil war. At that time, threads
were a mixture of the then fledgling metric system (French) and a
conglomeration of American threads. Thread shapes were quite different
as well. The next big standardization came from- you got it- the
automotive industry (SAE is of course Society of Automotive Engineers),
and I guess, only a guess, that the reluctance to change to metric
really came from the automobile industry. At one time, the Volvo had
SAE, Metric, and Whitworth fasteners in it, and not too long ago at
So, I think that manufacturing inertia rather than the housewife might
be to blame for the US still being SAE and all that implies. As bolts
go, so do the rest of the measurements.

Chris Albertson
> On Thu, Dec 15, 2011 at 9:29 AM, Dan Kemppainen <dan at irtelemetrics.com>
> wrote:
>> On 12/14/2011 3:59 PM, time-nuts-request at febo.com wrote:
>>> It's not like metric is totally absent.  We drink 2 liter cokes and
>>> defend
>>> ourselves with 9mm pistols.   Our cars use mostly metric parts.  Even
>>> ham
>>> radio operators, arguably the most jingoistic and set in the past
>>> bunch
>>> around, get on the 80, 40, and 20 METER bands.
>> I agree with you, and funnily enough the rest of the NATO world uses
>> 7.62mm
>> and 5.56mm rifles. (Both were originally based on standard inch sized
>> rifle
>> cartridges designed in the US)
>> The problem in converting to metric would require replacing a lot of
>> tools.
>> For example Mills, lathes, and other machining tools and measurement
>> devices
>> are expensive, and last for decades.
> Can you point one even ONE machine shop in the US that can make metric
> parts?  Those guys would have gone out of business years ago.   Also
> how many are still using hand cranks and reading veneer scales?   Even
> small one man ships are using CNC now.
> The US is slowly converting.  It will take a long time.  Even now if
> you go to Home Depot and look at plywood you see the better (non
> construction) grades sold in even millimeters with the inches being
> some odd number of 32nds approximation.   This will slowly creep into
> more and more products.
> So the debate is silly.  If the US should convert???  No.  the only
> question is how fast are we converting and when will we be fully
> converted.   Not even if this will happen, it will.
> Chris Albertson
> Redondo Beach, California
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"Neither the voice of authority nor the weight of reason and argument
are as significant as experiment, for thence comes quiet to the mind."
R. Bacon
"If you don't know what it is, don't poke it."
Ghost in the Shell

Dr. Don Latham AJ7LL
Six Mile Systems LLP
17850 Six Mile Road
POB 134
Huson, MT, 59846
VOX 406-626-4304

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