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

bownes bownes at gmail.com
Thu Dec 15 14:51:14 EST 2011


Those bolts would be whitworth. 



On Dec 15, 2011, at 14:43, "Steve ." <iteration69 at gmail.com> wrote:

> The laboratory where i work obviously reports results using the SI metric
> system. There is one exception though, and that is the energy side,
> specifically calorimetry. At first glance the calorimeters appear to
> normal(SI, that is). They take mass in terms of the gram, measure
> temperature by degree Celsius, and internal calibration is stored as
> calories.
> 
> The exception is the result is reported in BTU/ pound!  How's that for
> mixing systems?
> 
> On the electronics side of things it's even worse. Technical documents
> mixing and matching between systems. It's very common to see specifications
> cited partially in MKS and CGS with no correction terms.
> FYI:
> MKS = Milimeter Kilogram Second
> CGS = Centimeter Gram Second
> 
> I've seen two other systems, but their names are eluding me at this time.
> Also, I've come across bolts that are not SI, nor SAE. I believe they are
> considered a british thread but i'm not certain.
> 
> Steve
> 
> On Thu, Dec 15, 2011 at 1:15 PM, Don Latham <djl at montana.com> wrote:
> 
>> 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
>> that.
>> 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.
>> Don
>> 
>> 
>> 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
>> www.lightningforensics.com
>> www.sixmilesystems.com
>> 
>> 
>> 
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