Wasn't sure whether to put this under road signs or here, but since its car related rather than signage related - maybe it should go here.

Anyway - I can confirm that Martin is correct regarding tech data in VW handbooks.

This is literally a true story that happened just 10 minutes ago.

I'd stopped at the Petrol Station to get a newspaper and a pint of milk (well the missus got them, I was merely the driver).

As I was persuing the newspapers, with said 'missus', a middle-aged lady came up to me and the conversation went something like this:

Lady: Oh hello, I hope you don't mind me asking but I'm not technically good at this. I'm with my daughter in the polo over there (points) and we want to check the tyre pressure. But I can't work out what the book means
(hands over book to me).
Lady: you see it says 1.9 but the numbers on the machine are much bigger than that. What am I doing wrong?
SteveH: Ah, don't worry - you are doing nothing wrong. This book is showing the metric version of tyre pressure. The machine you are using has a digital readout and shows PSI. As it so happens my Dad used to be in the tyre business and to a certain degree you can safely put in 26PSI.
Lady: So its ok to put 26 in the tyres?
SteveH: Yes. For your car that will be fine.

On our journey home I mentioned this to my missus who works for a company involed with the customer relations side of things at VW. She was surprised that the info was missing.
I explained that being a German company there will be a little arrogance in regards to what information 'we are permitted to use'. Besides - the customer will have bought the car (ie handed over the money) before they see this form of arrogance in their owners guides.

I told her she should raise this 'real life' issue during one of her 'high brow powermeetings'*





(* That was a deliberate attempt at a David Brentism)

Do pressure gages not list PSI and metric on them over their? I will admit that I don't have experience with many tyre pressure gages over here; but the few I've used usually have both metric and English units on them.

Above post was by me.

Some have BAR *and* PSI but most have PSI *only*.

However the one I was talking about was a new style computerized one.

Basically you press an up or down button so that the LCD read-out says the PSI that you want. Then you apply the nozzle to the tyre valve and it will let-down or pump up the tyre for you and stop when the desired pressure is met.

<<However the one I was talking about was a new style computerized one.

Basically you press an up or down button so that the LCD read-out says the PSI that you want. Then you apply the nozzle to the tyre valve and it will let-down or pump up the tyre for you and stop when the desired pressure is met.>>

Ah, yes, those new LCD ones. Actualy I didn't think about it untill after I posted, but my newest tyre gage is a LCD one just like what you described and it is PSI only. I had forgotten about it because I lost it about a year ago and have been using my old analog one that is PSI and kPa on it. In fact I don't recall ever seeing a digital one that shows anything except PSI, just the analog ones that have kPa and PSI.

Steve, I take it your little story was an argument for metrication? Life really would be more simple if we stuck to one set of units. Good to see you've finally seen the light.

SteveH wrote

<<
I explained that being a German company there will be a little arrogance in regards to what information 'we are permitted to use'. Besides - the customer will have bought the car (ie handed over the money) before they see this form of arrogance in their owners guides.
>>

This is a mis-representation of fact adn Steve knows it. The UK law *requires* that bars/kPa be the primary unit of measure and that psi may be used in addition as a supplemenatary unit of measure. If a German company reads the UK law and publishes their handbooks so that the handbook complies with UK law and the UK garages choose to ignore the law, it the the UK garages that are being arrogant, not the German manufacturers. It is also the UK Government who is being gutless and spineless in bending down in front of a few little-England fanatics rather than enforcing a legally-required safety measure, even if it means that people might loose their lives as a result of their inaction.

<<As it so happens my Dad used to be in the tyre business and to a certain degree you can safely put in 26PSI.>>

Apart from the whole "units" issue, isn't 26 psi rather low? Most of my recent cars have required 32-35 psi. My low tire pressure warning goes off at 30 psi (just had it happen recently and checked)

In US, pressure has to be shown in owners manual and on a sticker on the door or door jam (driver's side, B-pillar) and be in listed in both psi and kPa (not that many use the kPa data)

I don't know exactly what the law says in the UK, but if we assume that VW follows the law, then the tyre pressue is in the owners manual in either bars or kPa (psi is not a legal requirements and in fact after 2009 it will be unlawful to print the tyre pressure in the manual in psi). In addition the pressure can either be on the door jam or under the petrol cap. (WHen you take a driving test the examiner can ask you to show him where the tyre pressure can be found and myu children's instructor was certainly happy for it to be found under the petrol cap).

Andy - that bait ain't working.

<<This is a mis-representation of fact adn Steve knows it. The UK law *requires* that bars/kPa be the primary unit of measure and that psi may be used in addition as a supplemenatary unit of measure.>>

You are talking absolute tosh and obviously have no idea how the car enthusiast fraternity talk.


<<, it the the UK garages that are being arrogant, not the German manufacturers.>>

So by responding to the wishes and requirement of the people the petrol stations are being arrogant?
Have you been at the vodka?

<< It is also the UK Government who is being gutless and spineless in bending down in front of a few little-England fanatics >>

you cannot be serious! do you now anything about car enthusiasm?

<<rather than enforcing a legally-required safety measure, even if it means that people might loose their lives as a result of their inaction.>>

You are having a laugh. People have always used PSI. Telling them to use something else is the introduction of danger.



<<Apart from the whole "units" issue, isn't 26 psi rather low? Most of my recent cars have required 32-35 psi. My low tire pressure warning goes off at 30 psi (just had it happen recently and checked)>>

No - for a small hatchback - in this case a VW polo - 26 is just right

<<(psi is not a legal requirements and in fact after 2009 it will be unlawful to print the tyre pressure in the manual in psi).>>

It won't happen. Don't stake your life on it.
Will they also ban rolling roads?




Imagine if you are a keen fisherman, martin.
Now imagine that I know nothing about fishing.
How pompous would I sound if I started preaching about your hobby and how it will change in 5 years based on absurd notions that I like the sound of.
Know what I mean?

Steve,

Consider the scenario - A French driver who is confused by psi runs his tyres at 70% of pressure (10psi = 0.7bar approx) and as result causes a fatal accident. At his trial his lawyer draws the court's attention to the fact that the garage failed to obey the law. Not only would the driver be found not guilty, but the garage owner might find himself in court on a manslaughter charge for failing to observe the law regarding public safety.

A supremely proposturous situation which is not backed by just one example of it EVER happening despite the millions of haulage miles of foreign vehicles on our roads.

You are startting to sound rather silly, martin.

Incidentally - would you suggest that because this scenario has never happened with cars then no car tyre in the whole of the UK has ever blown out due to underinflation? Think about it for a while and hopefully you might see why what you're saying is just plain daft.


Finally - do you believe that air at petrol stations is served at a certain price per pound-per-square-inch?

Steve, there is always a first time.

ALso, I was not referring to the "Economic use" clause in the EU directive, I was referring to the "Public Safety" clause.

To be honest, martin, if i were you i would have shifted attention to a more "safe" ground ;-)

eg. if we were talking about DVDs and their sizes I would have shifted the conversation on to Vinyl records wwwway back!

Think about it.

<<
The UK law *requires* that bars/kPa be the primary unit of measure and that psi may be used in addition as a supplemenatary unit of measure. If a German company reads the UK law and publishes their handbooks so that the handbook complies with UK law and the UK garages choose to ignore the law, it the the UK garages that are being arrogant, not the German manufacturers.
>>
Actually, it is the British Parliament that is being arrogant by passing laws designed to suit the needs of the German company rather than the British people.

Bud, so that you know the prominant system of pressure here is PSI. Its all over the place. All car manuals I've seen show PSI. I was surprised to see that the woman's manual showed bar.

Near the tyre pumps there is a chart of cars and their pressures. Most have PSI while some (very rarely) have both.

The manual can be ignored in cases like this.

In my example I could not see a chart but this was a very large petrol station and I just wanted to give the lady advice.

I've worked in a tyre garage when i was younger (my dads). Most cars of a small to medium type are ok with 26psi.

Its safer to over-inflate than underinflate - btw folks. Overinflate will shorten the tyre life and make it a bit bouncy. Underinflating can cause a blow out. God knows what the woman in this example was thinking when she saw a figure of just 1.9 !

BTW - took delivery of my lovely new caterham - all the tyres on that are 20PSI (to my amazement)

Tut tut all this anti-German stuff.

We mustn't use the Bar coz it's German. Right, I see.
(Or one would think so from above)

Oh and er, don't forget - we mustn't use Fahrenhiet for same reason!

<<< This is literally a true story that happened just 10 minutes ago. >>>

Gosh!

"BTW - took delivery of my lovely new caterham - all the tyres on that are 20PSI (to my amazement)"

Yeah, Right, and I have got a Jowett Jupiter.

<<Tut tut all this anti-German stuff.

We mustn't use the Bar coz it's German. Right, I see.
(Or one would think so from above)

Oh and er, don't forget - we mustn't use Fahrenhiet for same reason!>>

Erm - did you know that VW is German?
Brainchild of the Nazi period 'VW' is translated to 'Peoples Car'
The first beetle was called something else to go inline with Nazi doctrine - I can't remember its name precisely - something like 'Peace through Freedom car'. Imagine ordering a load of them on the phone- how verbose would the conversation be?

"Stick" and "wrong end of" springs to mind, old chap!
Oh, and wasn't fahrenheit austrian?


<<<

"BTW - took delivery of my lovely new caterham - all the tyres on that are 20PSI (to my amazement)"

Yeah, Right, and I have got a Jowett Jupiter.>>

What the hell is one of them?

<<"Stick" and "wrong end of" springs to mind, old chap!
Oh, and wasn't fahrenheit austrian?>>

It does for me too. Except it's you at the wrong end not me.

And no, Fahreheit was German not Austrian.

Erm - I started the post!

I was 'having a go' at German BMW, not "German" BAR (infact I didn't know "BAR" was german).

Why didn't you just tell het to look at what is printed on her tires? Here in the US, the pressure is stated in kPA (PSI). Isn't this a universal practice?

Whenever I need to add air, and I can't remember what the pressure should be, I look on the tires. much easier then rummaging through the glove box for the manual.

BTW, 190 kPa is 27 psi, not 26.

What size tires were those that they need such a low pressure. Mine tires have a max of 300 kPa.

<Why didn't you just tell het to look at what is printed on her tires? Here in the US, the pressure is stated in kPA (PSI). Isn't this a universal practice? >

The tyre sidewall doesn't always give the correct pressure for the car. For example, the tyre's sidewall on my Saturn says 35psi; however, the correct pressure is 30psi for the front tyres and 26psi for the back. My previous Chevrolet had tyres with a sidewall maximum pressure of 40psi, however the correct inflation for the vehicle was somewhere closer to 30 psi. (That is always cold tyre pressure, it will read higher after driving a bit. If my tyres are hot I over inflate a little and then let out some air after the tyres cool so that they are at the recommended temperature)

If I'm not sure what pressure to use in car I usually just use 30 psi.

I've never had a car that recommends the maximum safe pressure that is listed on the tyre's sidewall, the manufacturer usually recommends a slightly lower pressure. From what I understand not following the manufacturers recommendation can affect the performance and safety of the vehicle.

You should refer to the manual for the correct pressure for your car, not the sidewall

<<Whenever I need to add air, and I can't remember what the pressure should be, I look on the tires. much easier then rummaging through the glove box for the manual.>>

As already mentioned, that is a BAD practice. The pressure on the tire is a MAXIMUM safe pressure established by the tire manufacturer. Depending on the weight (and weight distribution) of the vehicle, that may lead to overflation which wears the center of the tire tread, and may deteriorate traction and handling. Use what the auto manufacturer says which is chosen for best compromise ride, handling, traction, and tire life. In addition to being in the manual, by law, it has to be on a sticker mounted driver's side on either on the B-pillar or the door edge.

It is only slightly easier to read than squatting to read the tire, but it is the right pressure.

Thank you John, I was hoping you would add something to this. I knew you where supposed to use what the manufacture says but couldn't really remember why; thank you for the further information. I had also forgotten about it being listed on the door, much easier than looking for my manual when I forget.

Well, I learned something. I was always upset when I took the car in for service somewhere and the tires seemed less then full when I got it back. I never complained, I just filled them up to the 300 kPa mark on the gauge. Never really had problems. But now for the future I will check my door sticker and fill them correctly.

If VW is a metric-only company, how do you explain the statement below? It is the intro to an article reproduced by the Dozenal Soc. of America.

"Buy a Volkswagen tire in Germany and it is sized in inches—buy almost any canned food
in Europe and it is marked up primarily in ounces and only nominally in grams. Yet still
people argue that it is a decadent nation which will not adopt the metric system. Dr. Gilles
sees no reason for such a changeover—even in export business"

Several ways:
* The Dozenal Soc. of America are idiots
*VW (like all auto manufacturers including US) is metric, but they don't make their own tires (or probably wheels either). The "standard" for metric tires is a metric width, a percentage profile, and an inch rim diameter. So saying the tire is entirely spec'ed in inches is a bold-face lie by the Dozenal Soc. of America.
*The inch dimension for the rim also specifies a detailed rim profile (much like screw diameters tend to specify a standard coarse or fine thread pitch, hex diameter, etc). There was a metric rim size with unique profile which didn't work out too well, and no one specifies a metric rim any more.
*I'm American and can't speak to the accuracy of the canned goods claim, but based on how wrong they are on inch tires, I wouldn't bet much money on the claim. Perhaps a European can comment
*There are lies on the Internet, especially from organizations to whom agenda is more important than truth.

I would further comment the tire/rim subject was largely beaten to death in this thread:
http://www.network54.com/Forum/thread?forumid=101350&messageid=1115722872&lp=1116605705

JohnS-MI: "* The Dozenal Soc. of America are idiots
*VW (like all auto manufacturers including US) is metric, but they don't make their own tires (or probably wheels either). The "standard" for metric tires is a metric width, a percentage profile, and an inch rim diameter. So saying the tire is entirely spec'ed in inches is a bold-face lie by the Dozenal Soc. of America.
*The inch dimension for the rim also specifies a detailed rim profile (much like screw diameters tend to specify a standard coarse or fine thread pitch, hex diameter, etc). There was a metric rim size with unique profile which didn't work out too well, and no one specifies a metric rim any more."

Reply: John, as you seem to have a pretty good knowledge of car-makers and the auto industry, I'll ask you this. The article that is referred to, the one the DSA have reproduced on their site, goes back to at least the mid 1960s: would VW have been entirely sizing its tyres in inches back then? Would any European car-maker have used imperial/US customary units in production back in the 1950s or 60s? I'm interested to know.

<<Reply: John, as you seem to have a pretty good knowledge of car-makers and the auto industry, I'll ask you this. The article that is referred to, the one the DSA have reproduced on their site, goes back to at least the mid 1960s: would VW have been entirely sizing its tyres in inches back then? Would any European car-maker have used imperial/US customary units in production back in the 1950s or 60s? I'm interested to know.>>

I don't know; well before my time. They might have but I don't know it for a fact. The US auto makers didn't go metric until the early 70's. I worked for one and it was completely converted when I joined in 1978.

None of the English speaking nations looked too seriously at converting to metric until the 60's. I would argue that what may have been practice in the 60's in Germany is just a pathetic argument for whether or not to metricate in 2005 and demonstrates how little sense DSA makes.

I've never been in a European supermarket but what little experience I have with imported European foods says Giles is wrong or out-of-date on that too. Our farmers grow too much and most of my food is US produced. However, I buy some specialty imports: olive oil, flavored cooking oils, flavored vinegars, and loose tea. The liquids are all in milliliters, the tea in grams, stated "metric first and round" followed by odd ounces as US law requires dual labeling, but lets either unit be first.

It seems from the link John provided that even the tires and rims may not be made in inches even if they carry an inch name. I find it really grasping for straws that one has to pick out less than 1 % of the total components of a car to find something still called out in inches.

The important thing to me is the units I will have to encounter when doing repair work, if I decide to repair the vehicle myself. If I need metric tools to remove and replace metric nuts and bolts, need a metric torque wrench to tighten the bolts to the manufacturers spec as stated in the shop manual, and need to set certain gaps in millimetres, then the car is metric as far as I'm concerned.

The rim may be in inches, but the nuts holding my wheel to the base are metric. Again, i still need a metric tool to remove and replace those nuts if I have a flat. Knowing or caring about the rim size whether it is millimetres or inches isn't going to fix my flat for me.

So who really should give a hoot about the rim size?

<<The rim may be in inches, but the nuts holding my wheel to the base are metric. >>

In that other thread, I looked at dozens of wheel links I didn't post. I found it amusing the rim diameter and width were in inches, but the hub holes, bolt holes, and bolt circle were all in mm (as specified by the vehicle manufacturers). What a muddle. If applied to straws, it would be a 5mm x 10" straw.

JohnS-MI: "I don't know; well before my time. They might have but I don't know it for a fact. The US auto makers didn't go metric until the early 70's. I worked for one and it was completely converted when I joined in 1978"

Reply: The reason I asked was because I believe that just after 1945 and well into the 1950s when western Europe was reconstructing, a lot of European companies imported a lot of heavy plant, machine tools, etc from the US to make up for losses from WWII, or for equipment that had worn out as a result of wartime production and was no longer serviceable. The other thing too was that the US would have been western Europe's automakers' main export market in the 20 years following the war and they may have put at least some of their specs in US Customary units in order to increase their competitiveness across America, eg making & specifying spare parts in standard US units in order to ease supply and facilitate sales. Just a couple of thoughts.

It's possible there was some mix of metric and Customary based on what aid we offered.

However, this article doesn't contain many specs, but it implies the Beetle was originally designed in metric before the war. http://en.wikipedia.org/wiki/Volkswagen_Beetle

I remember (poor college) friends in the 60's complaining about needing metric tools to work on their Beetles, but I can't find any comprehensive specs from that era.

It would seem the US was in a position to destroy the metric system completely in 1945, but either blew the chance or felt it was a bad idea. Either way it allowed the metric system to flourish and spread world-wide and be a pain in America's side ever since.

???
The metric system has "always" had its supporters in the US. Maybe not quite enough for full-fledged conversion, but you could never get support for stamping it out.

The metric Act of 1866 was passed to make it legal for trade as some manufacturers needed to trade in metric with European countries. The Mendenhall Order of 1893 made metric standards the basis of all our weights and measures -- the yard and pound were declared to be decimal fractions of our prototype meter and kilogram. A 1904 act to make it the official measurement system of the US lost by only vote, and it was extensively used in all sciences and some fields of engineering.

In 1945, the US pound and foot weren't even exactly the same as the Imperial, that didn't happen until 1959.

"In 1945, the US pound and foot weren't even exactly the same as the Imperial, that didn't happen until 1959."


Really! You mean the size of the inch varied between us and the UK until 1959? How did that happen? So something made one inch long in the US would not be one inch long in the UK? How very interesting!

I knew we have still different ounces, pints quarts and gallons, but I didn't know the inch and pound were affected too. So that means the foot, yard and mile all were different too, unless the UK and US have different conversion factors between the different units of the same name.

So who kept their version and who changed or did all change? How does that effect things made before 1959 and after? Tell me more!

Ooops! That was me. I forgot to put my name in the block.

Daniel,
I recommend you download and read SP447 from the NIST site. It is a special publication on the history of US standards.

Probably our copies of the inch and pound always differed from Britain's, as metrology was nowhere near as good when they were made as today's. In 1893, by Mendenhall order, we retired our physical standards for yard and pound and used declared fractions of the meter and kilogram, based on recent measurements.

The British stuck with their physical standards until much later, and had the problem their yard was shrinking with respect to their meter.

The National Standards lab directors from at least the US, UK, Canada, and S. Africa (others may have too) got together and agreed on the modern value which gives 1" = 25.4 mm, 1' = 0.3048 m. The US adopted the value 1959-07-01.

From 1893-1959, the US used the fraction 1' = 1200/3937 m, (actually the figure was used from 1866, but wasn't an official standard until 1893) which differs by 2 ppm. That is now known as the Survey Foot, and still used in land measurment. But we adjusted downward 2 ppm. The British adjusted upward about 1 ppm, and the agreed value is what the Canadians had been using for a while. Note that everybody's meters were precise, it was the foot that changed. The pound changed minutely, around 0.1 ppm.

A lot of details are in SP447. If interested in this stuff, its a great read.

From

Daniel,

I probably should have made the point that these were very small differences in the pound and foot, parts per million, and most likely accidents of measure or construction in earlier years.

Whereas the gallon, the bushel and all their submultiples were consciously chosen to be different values. Parliament defined the Imperial gallon (and Imperial bushel = 8 gallons) in 1824. The US completely ignored this and adopted the Queen Anne gallon (231 cubic inches) and Winchester bushel (2150.42 cu. in) which Parliament had approved in 1707. These had been traditional in the colonies and were formally adopted in the US in 1832, bypassing the Imperial gallon. The Imperial gallon is 20% larger than the US, and the bushel is a few percent different.

Re: VW July 3 2005, 5:54 PM
JS
It's possible there was some mix of metric and Customary based on what aid we offered.

metre
Looking at VWs history confirms that it was always built in metric. Even if circumstances forced German producers to use inch designed machine tools, it was conceived and originally built in metric. Most of Germany’s economic success after the war hinged on the fact that it was forced to construct new and better machine tools und therefore modernise its production process while Britain and America still used their wartime tools. America imported machine tools for the first time in the late 50s, something it had never done before.

http://people.westminstercollege.edu/staff/bknorr/html/history.htm
http://www.ukcar.com/history/Volkswagen/

<<Why didn't you just tell het to look at what is printed on her tires? Here in the US, the pressure is stated in kPA (PSI). Isn't this a universal practice?

Whenever I need to add air, and I can't remember what the pressure should be, I look on the tires. much easier then rummaging through the glove box for the manual.>>

This implies that you think that the same tyre on a massive vehicle would have the same pressure as the same sized tyre on a tiny vehicle.

I really can't believe you put the same PSI in your tyre as is stated on the tyrewall. Mine say 50PSI - I would NEVER put that in!! It's a max pressure guide.

Didn't you find it suspicious that when you drove over a speed hump you landed 200yds further forward down the road and jumping over about 3 cars? Or that your tyres started to get bald in the middle?

Although not as unsafe as underinflating it can cost you dearly in premature tyre wear. Mind you, it could be a price worth paying just to have that enviable position of being able to say metric words quite a lot (even though garage pumps WILL NOT have kpa on them!).

<<It would seem the US was in a position to destroy the metric system completely in 1945, but either blew the chance >>

You are starting to sound increasingly bizzarre. Are you saying that anyone who chooses the imperial system of weights and measures also wants all-out war on metric measurements? Or is this just a mirror reflection of your own point of view?

I'm just saying the primary metric users were destroyed or damaged heavily and the US had the opportunity to rebuild these economies along US units. It isn't a matter of declaring war on metric, but taking the opportunity to recreate things to your own advantage after they were destroyed anyway.

If the US had done that everyone today would be using US units and the metric system would have vanished. Now the whole world is metric and the US has to deal with two opposing measurement standards while almost everyone else just uses one.

I'm glad they didn't.

Make no mistake, Uncle Sam tried very hard to force his outdated units on everyone and succeeded with quite a few. Luckily trying to foist them on the UN failed dismally. Nearly all nations, dependent on America or not, rejected that ludicrous idea. Had they not done so, the whole world would waste precious time and money on working with units that make simple calculations often a nightmare.

<<I'm just saying the primary metric users were destroyed or damaged heavily and the US had the opportunity to rebuild these economies along US units>>

Yes, I forgot, the films show that America won the war - thanks for reminding me.

BTW - The day just one "proper" economist says there is a 'metric economy' or 'imperial economy' will be the day I eat my very first hat.

It's a bizarre notion, up there with the "lets metricate time" brigade and the "the euro will kill imperial" nutbags.

This thread is not about metricating time nor about the euro. So why are you bringing it up? This is about the US having had an opportunity to make the US English system the world standard in 1945 and not doing it. Thus allowing metric to overtake the world.

Can we stick to this subject please? Start another thread if you want to discuss metric time or discuss the euro on some of the already open threads on that subject.



I admit, though they did succed in changing western European air space to feet. It was in metres before the war.

You don't honestly believe that do you?

<<So why are you bringing it up? >>

I was showing what a ridiculous idea it was to suggest that the economy is based on how people measure how long things are.

You avoided it well though - congrats!

I think you either don't read the posts or you don't understand what they mean. I suggest you find a school that offers a course in reading comprehension and sign up for it.

I would but I couldn't understand the application form.

Metre: <<Looking at VWs history confirms that it was always built in metric. Even if circumstances forced German producers to use inch designed machine tools, it was conceived and originally built in metric. Most of Germany’s economic success after the war hinged on the fact that it was forced to construct new and better machine tools und therefore modernise its production process while Britain and America still used their wartime tools. America imported machine tools for the first time in the late 50s, something it had never done before.

http://people.westminstercollege.edu/staff/bknorr/html/history.htm
http://www.ukcar.com/history/Volkswagen/>>

Rip's reply: Metre, when did circumstances force German producers to use inch-designed machine tools? In the immediate postwar years, up to 1950? Before/after this?