Trying out metric

Here is my bit of info. I went on a bolting course given a Swedish bloke about 10 years ago.
He recognized my accent as Rhodesian not South African.
He told us fine threads were an attempt to stop nuts coming loose before effective locking systems were developed.
He told us that no-one was doing any research on Inch bolts, all was being done on metric bolts.

I took some science classes at the local college and realized why metric struggles here. The compulsory Imperial/metric conversion lessons are seen as not much more than arithmetic/mathematics exercises. As a child overseas I remember the change to metric. At the beginning of the school year everything went metric -that's all you learned. All new machinery was metric. We learned to convert because all existing equipment was in Imperial. S.Africa went so far as to ban any Imperial measuring equipment - no metric/inch tapes etc allowed.

I know it's a super old post from a super old thread but I had to laugh at Lew Merrick's comments about what the SI units were based on and how they "screwed up" the calculations. While it's true the definitions have been altered and refined, ever closer to a 'perfect' and repeatable quantity, they didn't "screw up" the calculations, it was just the best standard they could apply. Meanwhile, Lew doesn't mention the basis of the definition of an inch (width of an 'average' man's thumb) or foot (length of an 'average' man's foot) or yard (length of an 'average' man's belt), etc., etc. And what did they finally settle on to truly define the inch, foot, yard, pound, etc. - they are all now officially defined against the metric standard.

Oh, and the Mars lander (Mars Climate Orbiter) that was lost was due to a Lockheed-Martin failure where their equipment produced output in American customary units when the rest of the mission expected (and as they were contracted to provide) SI units. No "powers of 10" issue there.

Cogsy, I'm on your side. Like you I live in Australia which converted to metric in 1966 with what is acknowledged as being the most successful metrification project ever ran. Like you I am old enough to remember the conversion and being taught how to do maths in imperial units in school. Wow! how good was it to work in litres instead of pints, quarts and gallons!

Yes I remember we got dragged kicking and screaming into the metric system but it all changed in 1978 when I started to study engineering at University. In semester 1 we had to purchase a little book called "SI units" that was filled with conversion factors and explanations of the more complex metric engineering units. About once every 5 years, I still pull it out to check to check something like the relationship between kPa and bars, but I've never referred to it for conversion factors for the last 30 years.

Like you, during those early days, my head became filled with useless conversion factors like 25.4, 3.28. 0.3048, 2.471, 2.204 and many others. But eventually I succumbed and banned imperial measurements from my life and can now use those brain cells for other purposes. I recall, how I could once work in fractions with ease, but now it is a distant memory. I have a set of AF sockets I bought way back in 1978 that have not been used for years....

The last conversions in my mind to fall were land areas (it was much cooler to say I grew up on a 100,000 acre property than one that was only 40,000 Ha). The other one was rainfall. 100 points was embedded much more deeply than anything else given my rural background where rainfall was so important as it was almost a religious experience to empty the rain gauge when it finally rained (25mm was soooo boring).

I am pleased you corrected the reasons for the loss of the Mars spaceship as the excuse offered also clashed with my memory of the incident. Lets face it. Every major engineering project in the world has used SI units for years and this project was bought undone by a team that did not use them.

The fact remains that only 3 countries in the world cling to the imperial system. One of them actually corrupted the base units so back in the day, I had a whole host of secondary conversion factors for US gallons vs real gallons.

I just did a bit of quick research on Google and it just so happens that of there are 7 billion people living on this planet. But those 3 countries represent just 5.38% of the worlds population.

Eventually, you guys in the US will succumb and you will finally acknowledge you are a very small minority group. You will embrace the global standard. Yes, there will be much gnashing of teeth and wringing of hands just like there was in Australia back in the 60's and 70's. But remember, you are a country of 318m people and billions of others have converted to metric and survived. Surely, such a small handful of people can also make the grade.

I found a very interesting document by the NIST on metric in the Us. http://https://www.nist.gov/sites/default/files/documents/pml/wmd/metric/1136a.pdf

Looks like a lot of government purchasing is now in metric, but we still have the 'freedom' to use whatever we want, hence the mess of units.

As SI units are the official 'language' of science, it's interesting to hear seminar talks from American scientists fluently, and intuitively, speaking in SI units. They were bought up using imperial for everything but their careers necessitated a change which they obviously underwent. I wonder what units they use in their 'everyday' lives, do they think of a summers' day in degrees c or f, meat in lbs or kg, milk in L or fl.oz? I'd guess whatever they're most comfortable with, which I further assume is metric. My parents were born, raised and working full-time for years before metrication but completely made the change long ago - except, as Rod says, they still live on acres of land.

Edit to add: Ron, your link was off a bit - https://www.nist.gov/sites/default/files/documents/pml/wmd/metric/1136a.pdf

Another edit: I read the paper Ron found and it was interesting, just a note though - mL is a volumetric measurement, for dry ingredients for a recipe (or even quantities in chemistry, etc.) we use mass measurements in grams. We only use mL or L for fluid or gaseous quantities.

In my first year at university in 1978 when most of us worked in imperial units in everyday life, the lecturer calculated the power output by an engine in SI units and came up with the result in kW. It took half a blackboard.

He then redid the same sum in imperial units and came up with the same result in Horsepower which saw him fill 3 blackboards before announcing to the assembled students "And that's why in Australia we prefer SI units! It was a powerful incentive to get our head around the new SI units. I had never even heard the term SI units before.

I have always wondered at U.S. tv shows like CSI and Bones which routinely quote metric units for distance and weight. I thought they were just trying to be "scientific".
Ian.

In interacting with my own doctors and taking my mother to hers, It's mostly metric: Doctor tells me the size of things in mm and tells me to drink 3 litres of water a day. Docter tells Mom to gain 10 lbs and drink 10 8-oz. glasses of water.

My wife is a nurse and we tend to use units interchangeably without problems.

In addition to a fondness for metric units, our personal inclination is to use 24-hour time: Every clock we have that allows it is set to do so. I was never in the military, but I think it makes more sense.

--ShopShoe

had a mate years ago, when we were kids building a fort, tree house, go cart etc. he would say cut this off at 3feet 1 inch and 5mm. as long as i cut it at 3feet 1 inch and 5mm it would fit. if you look at a tape measure with inch/mm, it makes sense.

I was educated in a time when Australia changed from Imperial to Metrics and have worked in engineering for the past 47 years. Many of these years were on oil rigs both on land and offshore.
The idea of measuring distances by using fractions of a dead Kings smelly foot is difficult to understand when we have available a simple system based on the number of fingers on a standard person.
To be able to add in 10's is pretty easy.
I have even had to work with "oilfield" tapes where the feet" were divided into tenths to make addition and notation easier. It would have been easier to use metrics.
Congratulations on seeing the light.

It's probably a bit over the heads of some, but the arguably feasible answer is the 'Megalithic Yard' which the ancients calculated from the Planet Venus.

What remains is the Railway Gauge of 4 feet 8 and half inches which no one has yet to fathom( ouch). It certainly is not English and I went through all this with a French Professor of English. We were having fun with the origin of haggis and I reckoned that is was from the Norman French and the Grande Alliance of France and Scotland and merely meant 'minced' Well, the Railway Gauge is from the Roman Wall of which there were two and was obtained from the ruts of Roman Chariots which were ground into the stone of Hadrians' Wall.

And who adopted the gauge first, we know that it was from the wooden railways that took the coal down to the River Tyne and the first steam locomotives that used the gauge came from none than George Stephenson of Canny Wylam on the Tyne and his Rocket.

Laughingly, I seem to have quite a bit of that Wall as my boundary wall. There's a bit of Anglo Saxon stuff next door-- but I digress

Norman

Rig30mechanic said:

I was educated in a time when Australia changed from Imperial to Metrics and have worked in engineering for the past 47 years. Many of these years were on oil rigs both on land and offshore.

The idea of measuring distances by using fractions of a dead Kings smelly foot is difficult to understand when we have available a simple system based on the number of fingers on a standard person.

To be able to add in 10's is pretty easy.

I have even had to work with "oilfield" tapes where the feet" were divided into tenths to make addition and notation easier. It would have been easier to use metrics.

Congratulations on seeing the light.

Click to expand...

Starret sells steel rules with the inch divided into 50ths and hundreds. In the machine shop it makes perfect sense.

There us a lot of stupidity in America with respect to the metric system. I work in the optics industry which has pretty much always been metric. Companies will build tooling and machinery with all the drawings in english units. Yet the parts being made are very much dimensioned in metric units. Strange.

Inches were not always equal to 2.54 cm. Inches measurements were not as long in different countries. In the same period before it was determined that 1 inch should be equal to 2.54 cm in 1959, the definition was determined in an agreement between the United States and the British Commonwealth in 1958.
1 Scottish inch = 2.5441 cm, 1 French inch = 2.70 cm, 1 Roman inch = 2.47 cm, 1 Norwegian inch 2.614 cm.

England was traditionally the largest export market for Norwegian wood loads, and then it was practical that the British inch is slightly below 1 mm shorter than the Norwegian inch. The wood plank that were cut after Norwegian inches up would then get about the same measurements in English inches after drying.

How painful and expensive could it be when a German workshop used a working drawing with dimensions set on the drawing from Italy to make spare parts for a locomotive that was manufactured in Italy and then find that the parts did not fit due to the machine operator did not think that the measure were measured after Italian inches and measured with a German inches measuring tool during work.

"Give him an inch and he'll take a mile"

I wish the local Chinese lathe vendors would give us the option of metric or Imperial like they do in the UK. I asked Big Dog if they would bring in a metric machine and received an emphatic NO. So much for customer satisfaction.

Infact the choice of imperial versions here is getting less, many of the latest hobby lathes are now only being sold in metric in the UK.

Here in Slovakia I can buy 10 mm drill bit for 1.5 EUR
but half inch drill bit costs me 10 EUR.

I am happy we have the same circle division to 360 degrees
and time to 24 hours.

kadora said:

Here in Slovakia I can buy 10 mm drill bit for 1.5 EUR
but half inch drill bit costs me 10 EUR.

I am happy we have the same circle division to 360 degrees
and time to 24 hours.

Click to expand...

I suspect that a 1/2" drill will be more than that in the UK.

However, there is a shortage of 'tenths of a millimetre' drills as well.

I'm on with a metric Eccentric tool and cutter grinder which calls for such drills and as most drill chucks are far from accurate( mine especially), I'm forced to break into my sets of Fractional and Letter and Number drills to compensate.

Not a perfect solution but worth a mention?:wall:

Norm

No problem to buy 12,7 mm drill who are same as 1/2" inches drill

https://www.amazon.com/dp/B0033B0STQ/?tag=skimlinks_replacement-20

Norm

Should not be a problem getting metric drills in 0.1mm steps, I have had a 1.0-6.0mm set for about 30 years and never had a problem buying replacements. Got a 6.0-10.0 set a few years ago and easy to top that up if needed.

Just received the new catalogues for Tool Station and Screwfix.

Plenty of drills but 0.5mm intervals. It happens when you are 87. Not a lot of us about but if you are COPD, a post box means a taxi!

But thank you, it may help others

Norm