A topic for Glenn or Harold re: metrics

[rmac]

All this is probably why I prefer an adjustable wrench ..

Um, imperial or metric?

[Bill Shields]

I have several of each

[John Evans]

The best thing about SAE/Imperial is the ease of threading on a lathe !! X number of threads per inch ! I was first exposed to metric in about 56/57 when I first started playing with motorcycles. My 125CC Harley Hummer was a copy of a German DKW design with pretty much all dimensions converted to SAE. But do note the displacement was given in Metric's 125CC NOT 7.5 CID !!! Having had bikes from dang near every country that made such I have been around a lot of metrics. And standardization in metric HA!! German 6 MM nut 11 MM rest of the world 10 MM. Japan uses 14MM bolt head most of the rest of the world 15MM. Old Volvo's were built to SAE from a METRIC country.

[tornitore45]

They built the pyramids with cubits and knotted ropes. If you have a reliable unit every system is operational.
I am not a machinist; I am an electrical engineer, perfectly at ease with both systems, now after moving from Italy.
My first transformer design in US was a nightmare. You have to calculate how many 32 Gauge turns fit side by side in a 1+11/64 coil formers
Then you need to calculate how many windings layer fit in the available height. The available height is calculated subtracting a couple of dimensions given in fractions with different denominators.
Mind I have no problem with fraction but it takes a bit more mental gymnastics that subtracting two decimal numbers.
As for threading the Imperial system is more rational as TPI but they blew it with handling the Nominal size with fractions and/or #.
The formula 0.060+0.013x# is easy enough but a M4 screw is just 4mm, and a M2.5 is just 2.5mm
My point is that there is no better system in absolute, I favor the metric but can work on both and even build metric parts on my Imperial machines. Historically each system developed separately and great technological achievement were reached in both systems.
But given that 95% of the world is metric is about time for the US to get on the bus.

[Harold_V]

But given that 95% of the world is metric is about time for the US to get on the bus.

I suspect that isn't going to happen. The cost of transforming our entire manufacturing industry to the metric system makes it a not-so-great idea.
Why fix it when it isn't broken?

H

[Bill Shields]

It is a gradual process...not a flip of a light switch.

Remember when USA made autos were all SAE...then had metric drivetrains (transmissions and engines)...and most all other parts were SAE?

Where are they now?

As H says..why fix when not broken?

Companies in the USA purchase new metric equipment from elsewhere in the world.

The strangest things pop up as metric only that people never think about. Ever measured a dental implant?

[tornitore45]

Except for a 2x4 and a sheet of plywood most of the US industry has already shifted to metric.
There are things like the train Gauge (which is what it is in many metric countries) and the electronic chassis module 1.75" that is never going to change.
The resistance is in the mind of the consumers that will never adapt to buy gas by the liter or butter by the Kg until several generation in the future.
Anyway, the real shift has happened where it counts: in the factory and laboratory where much calculations are going on. Buying gas by the gallon is a simple matter of accounting, would make no difference if we bought it by the bucket.

Ever measured a dental implant?

Or anything related to optic?

[mklotz]

But given that 95% of the world is metric is about time for the US to get on the bus.

I suspect that isn't going to happen. The cost of transforming our entire manufacturing industry to the metric system makes it a not-so-great idea.
Why fix it when it isn't broken?

H

More importantly, as long as it remains inferial, it is broken. The world market for inferial dimensioned products is already small and continues to diminish. Who wants to maintain an inventory of inferial repair parts when metric products are cheaper and more readily available?

[Bill Shields]

giggle...all you have to do is look at the UK...where they have been officially metric for how many decades? Since 1960's ??

road signs are still in miles...

know why?

$$$ too much to replace them if they aren't 'broke'....

hard core practicality...

[NP317]

But given that 95% of the world is metric is about time for the US to get on the bus.

I suspect that isn't going to happen. The cost of transforming our entire manufacturing industry to the metric system makes it a not-so-great idea.
Why fix it when it isn't broken?

H

More importantly, as long as it remains inferial, it is broken. The world market for inferial dimensioned products is already small and continues to diminish. Who wants to maintain an inventory of inferial repair parts when metric products are cheaper and more readily available?

I began working for a USA Medical Electronics designer/manufacturer in the late 1970s. By 1980 we were going metric to allow international sales.
That change was successful, as it has been for many other US manufacturers. Those remaining, anyway.

During the Carter presidential administration the USA was going metric with interstate roads signs in miles and kms.
The Reagan admin spent tens of millions of dollars reversing that progress. I never understood why. Politics, not usefulness.
And my two Seattle Sons always preferred to watch the Canadian TV stations for weather, because it was all in Metric and made more sense to them.
They remain dual Metric/not metric.

Ben Franklin was wise.
RussN

[Harold_V]

More importantly, as long as it remains inferial, it is broken.

I pretty much understand that rationale, but from the perspective of a guy who has a hard time equating alternate units, it isn't broken.

I know I can adapt----I did it when I refined precious metals, and came to understand what a liter is. Problem is that a guy like me, with limited education and a head hard as a rock, is slow to learn new things. It's not a matter of one system being better than another, but the fact that I understand the devil I know, and understand that it most likely is not as good.

In my world, when I encounter anything metric, I quickly convert to *inferial* units, which I better understand. I must say, time has helped, as I now can visualize a milimeter, where, before, I could not.

I often think about the Gerstner full of measuring instruments and the screws on my machine tools. Do I ***really*** want to replace them??

I tend to think not.

H

[mklotz]

More importantly, as long as it remains inferial, it is broken.

I pretty much understand that rationale, but from the perspective of a guy who has a hard time equating alternate units, it isn't broken.

I know I can adapt----I did it when I refined precious metals, and came to understand what a liter is. Problem is that a guy like me, with limited education and a head hard as a rock, is slow to learn new things. It's not a matter of one system being better than another, but the fact that I understand the devil I know, and understand that it most likely is not as good.

In my world, when I encounter anything metric, I quickly convert to *inferial* units, which I better understand. I must say, time has helped, as I now can visualize a milimeter, where, before, I could not.

I often think about the Gerstner full of measuring instruments and the screws on my machine tools. Do I ***really*** want to replace them??

I tend to think not.

H

Being "slow to learn new things" is not a reason to avoid learning them. If it were, we'd still be living in the dark ages.

I've heard other oldsters avoid the issue by saying they refuse to give up their inferial tools. It's a hollow excuse. Nobody is suggesting that you need to do anything different in your own workshop. It's the nation that needs to change. The "but we'll need to replace all the factory tools" argument is, if not already dead, on its last legs. More and more, industry is moving to CAM and, with that, changing measurement system is just a software tweak.

The real problem is the people and their unreasonable stubbornness coupled with an education system that has given up teaching. Mathematics is still taught but reading machinist fora will make it painfully obvious that it is isn't being learned. Simplifying measurement calculation has no appeal to people who can't calculate much of anything.

The other annoying argument is the "rather the system I know" whine. Most Usonians don't know anything about American customary units beyond what little bit they might use in their narrow fields of work. That's why news reports have to use units like "football fields", "Olympic swimming pools" and "elephants" to describe things. The idea of a simpler system has no appeal to people who have none.

Add to all this the fact that they don't know what a measurement system is and what are the important features of a good one. I've written an article on this subject and was tempted to put it up here but it's probably too long for this group. Anyone who wants a copy can contact me via email and I'll provide a copy.

OK, rant over.