Re: Newbie question :) be kind...

"Wolf K." wrote:

Greg Procter wrote:
"Wolf K." wrote:
[...]
There's far too much made of the "logic" of the metric system. The thing
is, that those who tout the logic of the metric system think of a
measuring system as a thing in itself, somehow divorced from human use.
Measuring systems were made for human use, and any system that meets
human needs is good.

That lets the US imperial system out.

How so?

Take length for example"
You have:
- "miles": 5,280 feet.
- "nautical miles": 6,000 feet.(?)
- "Furlong": 10 chains.
- "Chains": 100 links.
- "Links": 0.66 feet.
- "Poles": 6.6 feet or 1/800th mile.
- "fathom": 6 feet.
- "Yard": 3 feet.
- "Foot": 12 inches.
- "Inch": 4 Barleycorns.
- "1/2 inch": 0.500 inches.
- "1/4 inch": 0.250 inches.
- "1/8 inch": 0.125 inches.
- "1/16 inch": 0.0625 inches.
- "1/32 inch": 0.03125 inches.
- "1/64 inch": 0.015625 inches.
- "1/128 inch": 0.0078125 inches.
- "thou": 1/1000inch.

Note that 1/64" (a commonly used dimension) is defined to _six_ decimal
places of an inch, or an infinite number of places (0.00130208333.) of
the base imperial measurement, which is one foot.
(the inch is of course defined as 1/12th of one foot, the "4 barleycorn"
definition now having being dropped - I was joking :-)


The very thing that makes the metric system logical
is irrelevant for most human uses. The most common use of measured
quantities is in buying and selling. It's significant IMO that the
typical quantities of traded goods are pretty much what they've always
been, just measured in different units. Eg, a loaf of bread weighs about
1lb, because that's a handy size for handling and slicing.

2 kg is also a handy size for cutting an slicing.

2kg? That's a monster. If that were so, we would see a lot of 2kg (4lb)
loaves. The hevier bread (pumpernickel, for example) are smaller in
volume, actually, so that their weight is about 1lb (half a kilo.)

Sorry, I meant 1/2 kilogram - my wife buys the bread.


Does it matter that in the metric system conversion between units is
easy? Very, very little. Even the people who find this feature handy
(eg, technical people) don't do it all that often. Most of the time you
just don't convert between units, because there is no need to do so.

I spend a lot of my time converting between units:-
Tonnes, Tons, US Tons, Hundredweights, Stones, Kilograms, Pounds,
Ounces, US Ounces, grams...
Nautical Miles, Miles, Kilometres, Chains, Metres, Feet, Inches,
Centimetres, Millimetres, 1/4"s, 1/8"s, 1/16"s, 32"s, 1/64"s, Thous, #
drills, wire gauges, ...
etc.

Yes, Greg, but you're unusual. Most people never convert. Some people do
it as part of their work or hobby, but not nearly as often as the
touters of metric believe.

This whole discussion began around _my_ frustration of having to use
metric and multitudinous US imperial measurements intermixed.


For the vast majority of human uses, standard sizes and dimensions are
far more important than the units used to measure them.

Agreed.

(Footnote)
Consider the standard intermodal shipping containers. These are all
specified in feet, because the ultimately successful version was
designed in the USA.

Who tells you these silly stories? The design came from P&O in the UK.
The ISO committee accepted the P&O standard.

Thanks for the correction, but it doesn't change my point.

The problem with a "standard" is that it is difficult to change once
it's set and accepted.


Does this faze anybody anywhere? Of course not.

Actually it does.
The height of a standard container has increased from 8' to 8'6" to 9'
over the years.

IOW, the original container was too small. So?

I worked in the container business from soon after it's inception
through the period when industrial pressures forced the increases in
size.
I liased with New Zealad Railways to move containers around the country.
Initially the loading gauge was marginal for moving a standard 8' high
container through some mainline tunnels as it tapered from 10' above
rail level at 45 degrees.
(3' high wagon deck and 8' width at 10') Most tunnels would clear the
upper corners of the containers (or v.v.) but some alignments
conflicted. (you only need one :-)
A few drop-decked wagons were built for branch-lines.

That was sorted fairly quickly, but then along came 8'6" containers and
we scratched the interior linings of a few more tunnels. A Railways
programme was put in place to lower the floors of main-line tunnels but
we (shipping company) had to stop taller containers going to some branch
lines.

The Lyttelton tunnel (major South Island port) had a tunnel built circa
1863 and this was electrified in the 1920s. The simple cure was to
remove the overhead electrification.

Within a couple of years 9'6" containers began to appear. (remember,
no-one actually told us these were coming, they just appeared on the
wharves for us to onload/offload)
This started a whole new round of track realignment, tunnel lowering,
tunnel daylighting, overbridge alterations, electrification raising ...
Meanwhile there was a whole rash of truckies getting jambed under
bridges.
Life was fun!


The length has increased from 20', 30' and 40' with US shipping
companies using all sorts of extended lengths.

Yup, and they do so because it's convenient to have different sizes. But
oddly enough, the latches and locks are all spaced such that a car built
to take up to a 53' container will also take 48' and smaller ones.

There isn't an international 48' or 53' standard.
Here in NZ we don't even get 10' or 30' containers because ships are
built with 20'/40' cells.
There are some 10' national containers in use but they can't leave the
country.


It
doesn't matter where the containers are made, they all fit the latching
and lockdown devices on truck frames, railcars, etc. That's all that
matters.

The standards make them interchangeable world-wide. US non-standard
measurements make US products damned awkward outside the US.
See how that works?

Awkward, shmawkward. Different size containers acn still be stacked
safely. I've seen 53' containers stacked on top of 48' ones, two 20's on
top of one 40' or vice versa, etc etc. The standards are in the latches
and locks.

Yes, the non-standard lengths are _extended_ 40' standard containers.
That makes them non-standard and unusable outside specific situations.

Besides, I notice that most widely used containers are
actually owned by Asian shippers. Odd, that they are more than willing
to build containers of those awkward US sizes.

They are _owned_ by Asian businesses, not _built_ by ... You can't put a
non-standrd length container on a ship, other than at the top of a
stack. An extended 40' container takes _four_ spaces and stops two of
those from being stacked further. In addition the container needs to be
offloaded and reloaded if any container in those four stacks needs to be
off-loaded.
Shipping between Europe and NZ, the cost of off-loading/reloading is
approximately equal to the cost of travelling that distance.
Under those circumstances the cost of shipping an over 40' container is
double that of a 40' container and several off-loads can double it
again.


It would be nice to have all kinds of other standards, and the ISO is
working on it. It's slow going, because no matter what standards are
adopted, someone is going to have change their tooling. The cost of
doing that may outweigh any supposed advantage of common standards,
especially if different markets have different expectations. Also,
"proprietary formats" may be held to have an advantage greater than
conformance to a common standard.

230 volts has been accepted world-wide.

Not so, 110-120V is still used in many parts of the world outside the
US, as anyone who like me has had to buy one of those converters knows.
What's worse than the voltage differences is the difference in plugs.
there are at least 4 different standards.

Europe and Asia are all busily converting to 230v as quickly as
circumstances allow.
230v AC is the standard.



For the record, I use both imperial and metric units, depending on my
needs and desires. I see no reason to be limited to one or the other of
these systems. Is this illogical? Of course it is. So what? I'm a human
being.

My milling machine is a "fixed" item - it doesn't change to suit my
needs.

Once again, you're not reading carefully, Greg. If you need a milling
machine, then you use the units that its internal measuring (setup)
devices use. Or else you use external measuring instruments to set it
up. Etc.

The (export) Sherline uses two measuring systems, metric (leadscrews)
and US imperial (assembly).

Your choice. The fact that you desire to model antique
locomotives merely means that you have to do what people never have to
do: convert units. IOW, in order to satisfy some desire or need, you
have to put up with more or less *** along the way. That's life. So?

What I'm modelling is a seperate issue.
Were I modelling say European Garden scale models I'd still need to
rebuild the machine to suit the size of component I'm making. I'd still
be faced with US imperial specific bolts and threads.

Let me just applaud a fine Australian/US product. The Sherline is as
good or better than _any_ equivalent product in the world, and the
pricing is far better than the few machines that are it's equal.
The major problem it has is that it does not conform to internationally
standardized measurements.


I use inches when framing (last summer I built a lean-to garden shed on
my house). I use HO scale feet when scratch-building. I use millimetres
when kitbashing plastic buildings. I use table spoons, teaspoons, cups
when cooking. Etc. Why? Mostly the result of familiarity with my
measuring tools, and/or availability of standard sized materials, etc.
IOW, as much as possible, I make it convenient for me. I see no reason
to switch it all to a single measuring system, just because someone else
wants it all to be a Single Logical System. So I'm crotchety and
unreasonable. That's my right as a human. Systems should serve us, not
the other way round, a principle that engineers and ideologues
repeatedly refuse to accept.(For the record, I started out to be an
engineer.)

Having to mix three, four or even five different measuring systems while
making a model is irritating.
This is a different issue to my prototype being built to an archaic
measuring system - I already have to convert for scale reduction so the
feet/inches/fractions simply get converted to millimeters. No problem, I
accepted that when I decided to model at less than 1:1 scale.

Take a simple example:
I want to fit a Kadee coupler to my new wagon. (I don't, but just say
....)

The mounting pad needs to be at 1 5/32" above the rails. (err, what's
that in real numbers? Rhetorical>)
So, I have to build a pad on the underside of the decking which is at
36mm.
That's 36mm - 1 5/32" thickness. 36 - 29.36875mm = (say 6.6mm)
My Evergreen plasticard is in .040" thickness, that's (more conversions)
six and a half thicknesses.

Right, mounting pad made - now I need to screw the coupler to the pad.
"Use a 3/8" 32-3/16" screw" - WTF is one of those??? Where would I buy
two from???
(not in New Zealand)
Will a metric size fit?
Will the metric size leave the coupler flopping back and forth if the
screw loosens???

You see, even without the machine tools the US imperial system is a
total pain to model making because of all those different measuring
systems involved.

Greg.P.
.