[time-nuts] time-nuts Digest, Vol 89, Issue 51
djl at montana.com
Thu Dec 15 15:12:09 EST 2011
The British Whitworth is a 55 degree thread instead of the 60 degree
SAE. BTU is a British Thermal Unit, hence BTU/lb. MKS is Meter Kilogram
Second, one of the precoursors to thee SI system.
> The laboratory where i work obviously reports results using the SI
> 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
> 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
> cited partially in MKS and CGS with no correction terms.
> MKS = Milimeter Kilogram Second
> CGS = Centimeter Gram Second
> I've seen two other systems, but their names are eluding me at this
> Also, I've come across bolts that are not SI, nor SAE. I believe they
> considered a british thread but i'm not certain.
> 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,
>> 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
>> 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
>> >>> defend
>> >>> ourselves with 9mm pistols. Our cars use mostly metric parts.
>> >>> 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
>> >> 7.62mm
>> >> and 5.56mm rifles. (Both were originally based on standard inch
>> >> rifle
>> >> cartridges designed in the US)
>> >> The problem in converting to metric would require replacing a lot
>> >> tools.
>> >> For example Mills, lathes, and other machining tools and
>> >> devices
>> >> are expensive, and last for decades.
>> > Can you point one even ONE machine shop in the US that can make
>> > parts? Those guys would have gone out of business years ago. Also
>> > how many are still using hand cranks and reading veneer scales?
>> > 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
>> > 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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> time-nuts mailing list -- time-nuts at febo.com
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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."
"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
Huson, MT, 59846
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