# Just how much does not being fully metric cost the UK economy?

One of our regular readers, John Frewen-Lord, has compiled a quiz, or rather two quizzes, to illustrate the waste resulting from the UK’s measurement muddle. The editors of Metric Views are unsure why a penalty of £1 per second has been chosen when scoring the quizzes – this pay rate surely applies only to top bankers, Premier League footballers and workers changing traffic signs for the DfT. If readers are equally puzzled, John will no doubt explain. Anyway, pen, paper, calculator and timepiece at the ready please ….

Most parts of our British life – and especially our economic life – have been metricated over the past 45 years.  Everything in our shops that is bottled or packaged is labelled in metric units.  We buy our fuel in litres, and our electricity in kilowatt-hours.  Our roads, buildings and houses are built to all-metric standards, using all-metric drawings.  Our babies are weighed on metric scales in our hospitals and clinics, our prescriptions are specified in milligrams and millilitres.  Appliances, cars, computers, mobile phones and pretty well everything else that started life in a factory will have been designed and manufactured to metric standards.

But there is one glaring aspect of our British life that has not yet converted, and that is our road signs.  We still use miles, yards, feet and inches on our roads.  This forces even our youngest schoolchildren to have at least a working knowledge of these outdated imperial units, when they are not needed otherwise.  Our politicians seem to think this does not matter.

But it does matter, for it adds an enormous cost to our British economy – but it is a cost that for the most part is hidden, yet is dragging our competitiveness down at a critical time.  This simple quiz, involving the kinds of everyday questions that we all have to resolve may just convince the sceptic.  The quiz, consisting of two sets of ten questions, one imperial, the other metric, is quite simple:

1. Answer one set of questions in total before going on to the second set (start with whichever set you prefer). The two sets of questions, although the same in principle, are NOT exact equivalents, so it is necessary to work out the answers for each set.
2. Award yourself a starting prize of £200 for each set of questions.
3. Time yourself in answering the first set of questions, using a stopwatch or timer, and then time yourself again when answering the second set.
4. The two sets of £200 prize money are then reduced by £1 for each second of time taken to answer each set of questions.
5. A further £25 is deducted for each incomplete or incorrect answer.
6. A bonus of £50 is added to each £200 if you do not use a calculator.
7. You are allowed to refer to textbooks or the internet to look up any necessary information during the quiz, but the time taken to locate any reference material must be included in the total time taken.

Imperial Questions (start your timer now):

1. A grounds keeper has a 4 acre field to mow.  If his mower is 6 ft wide, how many miles will he travel in mowing the field?

Hints: There are 4840 square yards in an acre. Divide the area of the field by width of the mower to obtain the distance travelled.

2. A car has an odometer showing miles and 10ths of a mile.  The driver sees a sign saying ‘No hard shoulder for 500 yards’.  How many 10ths of a mile will the odometer increment by the time the hard shoulder re-appears?

3. A room measures 20 ft 3 in x 30 ft.  How many square yards of flooring are required to cover the floor?

4. Your American customer has ordered a tropical fish tank measuring 20 in x 15 in x 10 in.  How many US gallons of water will it hold?

Hint: There are 7.4805 US gallons in a cubic foot.

5. How many pounds will the water in Q4 weigh?

Hint: 1 US gallon of water weighs 8.34 pounds.

6. A carton of soup contains 16 imperial fluid ounces.  How many cartons will it take to fill a 2 imperial gallon container?

7. A slice of meat weighs 1/2 oz.  How many slices will make up 5 lbs of meat?

8. An aircraft travels between two points 1000 miles apart, at an average speed of 500 knots.  How long will its journey take?

Hint: The UK nautical mile is 6080 feet.

9. An aircraft can hold 200 passengers.  If each passenger weighs on average 12 stone 9 lbs, how many imperial (long) tons will the passengers weigh when the aircraft is fully loaded?

Hint: There are 2240 pounds in a long ton.

10. A carpenter is laying a wood plank floor of 280 square feet. He can lay the planks at a rate of 8 linear feet per minute. If the planks are 5 in wide, how long will it take him to lay the floor?

Hint: Divide the area of the room by the width of each plank to get the total length of planks, then divide that total length by the speed at which he can lay the planks to get the total time.

(Stop your timer when you have answered question 10, and record your time.)

Metric questions (start your timer now):

1. A grounds keeper has a 2 hectare field to mow.  If his mower is 2 m wide, how many kilometres will he travel in mowing the field?

Hints: There are 10 000 m² in a hectare. Divide the area of the field by width of the mower to obtain the distance travelled.

2. A car has an odometer showing kilometres and 10ths of a kilometre.  The driver sees a sign saying ‘No hard shoulder for 500 m’.  How many 10ths of a kilometre will the odometer increment by the time the hard shoulder re-appears?

3. A room measures 5.75 m x 12 m.  How many square metres of flooring are required to cover the floor?

4. Your Australian customer has ordered a tropical fish tank measuring 40 cm x 30 cm x 20 cm.  How many litres of water will it hold?

Hint: There are 1000 cm³ in a litre.

5. How many kilograms will the water in Q14 weigh?

Hint: 1 litre of water weighs 1 kg.

6. A carton of soup contains 500 ml.  How many cartons will it take to fill a 3-litre container?

7. A slice of meat weighs 20 g.  How many slices will make up 2.5 kg of meat?

8. An aircraft travels between two points 1200 km apart, at an average speed of 800 km/h.  How long will its journey take?

9. An aircraft can hold 200 passengers.  If each passenger weighs on average 73 kg, how many tonnes will the passengers weigh?

Hint: There are 1000 kg in a tonne.

10. A carpenter is laying a wood plank floor of 24 m². He can lay the planks at a rate 2.5 m per minute. If the planks are 120 mm wide, how long will it take him to lay the floor?

Hint: Divide the area of the room by the width of each plank to get the total length of planks, then divide that total length by the speed at which he can lay the planks to get the total time.

(Stop your timer when you have answered question 10 and record your time.)

How well did you do?  The average person should be able to do the metric questions in under a minute in total, and without a calculator (£50 bonus).  But let’s assume you did take a whole minute.  At £1 a second deducted, you would lose 60 s x £1 = £60.  That would mean you win £200+50-60 = £190.  Not bad for 1 minute’s work (or even less).

But what about the imperial?  Likely a rather different story.  For a start, you will need a calculator.  Right away, you’ve lost the £50 bonus.  Second, instead of an average of 6 seconds a question, you will need an average of more like 20 seconds a question, even with a calculator, because of all the conversion factors. If you have to look up any necessary information, then longer still. Let’s say you knew all the conversion factors, and took 20 s a question.

At £1 a second you would lose £200 – (10 x 20 s x £1) = £0.  You would win nothing (negative if you got any question wrong).

Now you may say that easy numbers were picked for the metric.  Actually, easy numbers were picked for both metric and imperial.  Just that the metric numbers stay easy (that’s the nature of metric), and the imperial numbers will always get hard (too many weird conversion factors).

This was just a simple quiz, with simple everyday questions that we learnt (or should have learnt) in secondary school.  With metric, you might have won £190.  Imperial, you would have won nothing (or even been negative).  THAT represents a huge cost to our British economy.  Every day, people must make these conversions when working with imperial measures – conversions that are simply unnecessary when working in the metric system.   Those conversions cost TIME.  And as we all know, time = money.

In today’s world, where 95% of the world’s population works solely in metric, and where most of our British economy is already metric, we do not need to burden our children (or even ourselves) with having to learn and work in imperial measures – which they (or we) have to do in order to understand our road signs.  It is time to convert the last remaining segment of our British life, our road signs, to metric – and save our economy untold amounts in lost, unproductive time, as you have seen for yourself in taking this quiz.

Many people have said that the costs of converting our road signs to metric are too high.  Apart from the fact these costs have been grossly exaggerated, the costs of NOT converting are far, far higher – even if they are hidden. Hopefully this test will show that clinging to outdated and redundant imperial measures is a cost that, hidden or not, Britain, in the second decade of the 21st century, can ill afford.

(Answers to the quiz appear after the fifth response, below)

## Author: UK Metric Association

Campaigning for a single, rational system of measurement

## 21 thoughts on “Just how much does not being fully metric cost the UK economy?”

1. Ed the Yank says:

Hi John Frewen-Lord, Good job on the quiz! I will do it later, however eyeballing the questions one does see the difference in conversion factors and the math involved. It makes me think how much more work costs because, unlike the UK, our roads, buildings, and houses are built to all-common standards, using English based units. The same with most industries. And auto benzine is sold in US gallons but automobiles are built to metric standards.

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2. John Steele says:

Wait. We’re not supposed to “show our work?” I couldn’t come close to writing all that in the time allotted. The Imperial took me 3:53 and the metric 2:10.

However, if you need any answers, just let me know as I “showed my work.” Perhaps it is because I am an American, I found a couple of the hints to be red herrings as they seemed to lead to a less efficient approach to the problem (in my view).

I cheated on the airplane one and converted statute miles to kilometers so I could use the only definition of nautical mile that I know.

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3. Jake says:

UKMA: please send a copy of these questions to every MP in the land – with a stamped, addressed envelope for their reply. Any thinking person can see that metric is far easier than imperial and the UK really does look daft with its road signs being the only obvious remnant of ‘imperial’ (I hesitate to call it a ‘system’) in the public domain.

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4. Ezra Steinberg says:

This is a great posting and superb demonstration of the different utility of metric vs Imperial.

But there is an even deeper advantage that comes with metric (if the right curricula are created and taught in the schools) by highlighting and reinforcing the natural relationships that exist among the various phenomena that are observed in the physical and natural world.

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5. John Frewen-Lord says:

@John Steele:

It is intriguing that, being an American , you still took longer with the imperial questions than the metric questions, which, notwithstanding your contributions to USMA, you are probably much less familiar with. Imagine how much more difficult the imperial questions are to those who have never been taught imperial measures.

As a surveyor, working with metric measures now for some decades in South Africa, Canada and the UK, the imperial system is becoming ever more alien to me, even though it is what I initially grew up with. I just despair at how our imperial road signs must present a difficult – and totally unnecessary – challenge to our schoolchildren today, who are taught almost (but, by some accounts, not quite) exclusively in SI. It is a major handicap to them as they start their careers in a metric world.

You mentioned that some of the hints were red herrings. I did not set out to produce red herrings, although I deliberately did exclude the odd bit of vital information with the imperial questions. I (and perhaps some of the readers here) would be intrested in knowing what you regarded as red herrings.

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6. John Frewen-Lord says:

Here are the answers to the quiz:

Imperial
1. 5 1/2 miles
2. 2
3. 67 1/2 square yards
4. 13 US gallons
5. 108.4 pounds
6. 20
7. 160
8. About 1 hour 44 minutes
9. 15.8 tons
10. 84 minutes.

Metric
1. 10 km
2. 5
3. 69 m²
4. 24 L
5. 24 kg
6. 6
7. 125
8. 1 h 30 min
9. 14.6 t
10. 80 min

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7. John Steele says:

@John Frewen-Lord,

I worked in automotive and am probably more familiar with metric, certainly for technical work, although I can sometimes limp by in Imperial/Customary. The ones I would have approached differently than your hint:

I1. 4 acre/6 ft x 43560 ft²/acre x 1 mi/5280 ft (Americans don’t use yards for much, they are not a legal unit on road signs for example)

I4. I would have used the legal definition of a US gallon, 231 in³ exactly, avoiding the cubic foot conversion. (It is the Queen Anne wine gallon, Parliament defined it in 1705 and Congress in 1832.)
20″ x 15″ x 10″ x 1 US gal/231 in³

I8. I failed to notice your hint; however, I believe the UK adopted the International nautical mile a few years ago (1852 m) and previously used 1853 m for a number of years (basically to metricate 6080 ft). I used 1000 mi/500 kt x 1609.344 m/mi x 1 nmi/1852 m

M4. Since an answer in liters was required, I changed all dimensions to decimeters on the fly (1 L = 1 dm³)
4 dm x 3 dm x 2 dm = 24 L

“Red herring” might be too strong. The hint led in a direction I didn’t wish to go, and I used my own approach. Note: All the conversion fractions above would look a lot better over and under a horizontal bar; the operations performed would be clearer; however, I don’t know how to do that on the Internet.

I think the “average American” would struggle with most of the Imperial questions and would certainly need hints for the unique conversions on #6 and #8. They would not know 160 Imp fl oz = 1 Imp gallon, or be familiar with stones or long tons.

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8. Ed the Yank says:

Dear John Frewen-Lord:
One of those red-herrings could be that in school we learn there are 43560 sq ft in an acre and don’t bother with sq yards. There are 640 acres in a sq mile but that is showing off. 🙂

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9. philh says:

I would have imagined that anyone familiar with feet, yards and miles would probably convert the width of the mower in the imperial version of question 1 to yards and proceed from there.

I found question 2 interesting. It exposes the incompatibility of the yard in relation to the mile. 100 yd (or multiples thereof) are not a convenient fraction of a mile even though they both appear on road signs. Doing the imperial version required the obvious amount of effort but I could see the answer to the metric version by the time I finished reading the question.

On the whole the two sets of questions clearly show how much easier it is to work in metric on pretty well any problem to do with measurement, unless the parameters are skewed to be rational quantities of imperial units (even then it won’t always work).

Hopefully open minded readers will see this as a positive reason for change but I happen to know, alas, that it won’t convince the defenders of imperial units.

In my experience there are a spectrum of views expressed by opponents of metrication some of which are contradictory. On the one hand some will say that metric is not as convenient as imperial because of the size of the units and the large ratios etc. Some will even go so far as to say that the advantages of metric are exaggerated and that exercises like that above focus on a narrow unrepresentative aspect of everyday measurement usage.

On the other hand there are those who will argue that the ease and simplicity of metric is a disadvantage because it fails to exercise the mind adequately. They even claim that the metrication of the school curriculum has led to a fall in educational standards.

So what then is the problem? Is metric too hard or too easy?

On closer examination the argument claiming imperial to be easier is really founded on familiarity. If someone is subjected to feet and inches at an early age their view of the world will be in those units unless they make the effort to break away from it. But that doesn’t make imperial a better alternative.

It does take some effort to learn to think in metric and it isn’t just a question of adjusting to different sized units. The whole measurement philosophy of the SI is entirely different from traditional units. In SI each measurable aspect of the physical world has only one unit with the prefixes just being a convenient way of handling different orders of magnitude. Traditional units tend to be application specific and they often combine more than one unit in the same measurement which makes them inefficient. This distinction has to be understood to get the best out of the SI and to appreciate why the personal effort is worth it.

The other mistake a lot of people seem to make is to think learning to use metric means learning how to convert or translate back to familiar units. The conversion factors are awkard and leaves them with the impression that using metric is more difficult than working in the units they are used to.

The opposite charge that metric is too easy is a cynical attempt to counter the inescapable reality that imperial is cumbersome and inefficient. If there has been a decline in education standards following the change to metric in schools it is more likely to be caused by the failure to metricate across the whole of society which would enable kids to apply their knowledge outside lessons.

Sorry for the rant but I hope readers will appreciate my efforts to explain the reasons (as I see them) why people resist the change to metric in spite of its virtues, so vividly portrayed in John’s article.

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10. Alex Bailey says:

I would like to add to philh’s comments.

I’ve got fed up with the stance taken by some that somehow using metric dulls the mind and makes the British somehow mathematically challenged. If this were the case then American school children would be the best and British wouldn’t be that far behind in having to cope with 2 systems of measures… but they’re not, countries that use metric exclusively are.

I put a lot of this down to the uniquely British love of making things as complicated as possible and refusing to change. One example I’d like to offer is the number of people who speak of the roads in the town where I grew up, Milton Keynes. People always complain to me that they have difficulty understanding the road system which is based on a simple grid, instead claiming that the traditional hotchpotch found in almost all other towns and cities across the country to be easier to comprehend.

Brits need to learn that the way you’ve always done something is not necessarily the best and most efficient. They need to open their minds!

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11. DavidMM says:

An excellent example of the stupidity of holding on to the imperial ‘system’.

I lived for many years in South Africa where, when they metricated, they did it completely. In the last five years I have been in England, one of my pet rants has been the lack of change here. A marvellous example I saw was when they put the weights (actually, masses) of the university boat crews on the screen. To calculate the total weights you had to add stones, pounds, ounces and fractions of an ounce. Unbelievable!

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12. BrianAC says:

It may be my age, but I was taught the definition of an acre was 1 chain by 1 furlong or the area that can be ploughed by a single horse in a day. Thus I had to convert chains and furlongs into yards first. Need any explaination as to why I (one of the ‘old folk’) want to go metric?
I would like to try to kill the often quoted phrase ‘some older people (drivers) may get confused’. Well, yes, its the daft miles and yards with the odo 0.1 miles (176 yards, how sensible is that?) that has always defeated me. Add to this the ‘miles per gallon’ when we have not bought a gallon of petrol in ..what … 30 years? 40 years? It is still calibrated into new cars computers though. Good quiz, a good example of a stupid system, or should that be a non-system?

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13. Ronnie Cohen says:

Hidden costs of running a dual measurement system include time spent on conversions in both directions, separate production lines for dual measuring equipment for the UK and US markets, extra work on websites to include imperial units, time spent in British schools on teaching school children about imperial units, and extra time spent on more complex imperial calculations.

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14. Ezra Steinberg says:

As if there weren’t already reasons enough to convert all road signs to metric as soon as possible, here is yet another reason:

It turns out the UK desperately needs for many reasons (just like the USA, I might add) to be spending more money on infrastructure. An excellent reason to toss metrication of road signs into the pot as well.

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15. BrianAC says:

Showing our age, a mobility scooter was delivered this week for use by my wife.
One of the first things to do was to adjust the seat and arm rest heights.
First the seat height. Just looking I could see it was not metric, and required me to rake around the back of the shed for a couple of long forgotten half inch spanners and some odd ball allen key to undo the locking nuts and bolts, there was also something else a bit bigger than 14 mm that I had to force the spanner onto.
Now to the arm rests, mounted on the seat. Low and behold the bolts are metric! Just as well as one of the threads had already been mangled, presumably by someone trying to force a UNC nut onto it, and needed re-tapping, no problem with 8 mm, but I would have been stuck had it been whatever in inches.
So there you go, two sets of spanners just to adjust the b****y seat!
Nice to know our ruling elite seem to think this is a perfectly acceptable situation. Yes, it is new and I could have complained etc, but realistically who is listening? Certainly not my MP.

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16. Ray says:

Brian,

There is something about your mobility scooter that confuse me.

First, is this product new or used? If it is new and someone at the company botched up a bolt, you need to contact them and either have them replace the scooter at their cost or have them fix the problem the right way. Retapping damaged threads weakens the connection with a possible result of injury should the retap fail to support any load.

Second, Where was this unit made? Obviously in the US. I’m under the impression the US alone uses UNC and the UK in its pre-metric days used only Whitworth.

Most US products are a muddle of mixed metric/USC. Due to some companies using metric fasteners or the components being imported would explain why part is metric. Components made by non metric companies in the US will be in UNC, thus a hybrid product.

Here is where it would be beneficial to you to write or contact the US company and tell them of the hardship you encountered with their product due to mixing of systems. Also mention that USC tools are not available for sale in the UK and elsewhere, thus making adjustments using only metric tools difficult or impossible.

If they designed and built using only metric fasteners in the US it would not handicap any American purchaser as metric tools are readily available anywhere in the US, however, inch based tools are non-existent in the world and using inch based fasteners makes servicing the equipment difficult to impossible.

As a final note, I would inform them that unless they go fully metric in their use of fasteners, you could not honestly recommend their product to relatives and friends.

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17. John Steele says:

I can’t vouch for the total accuracy of this link but it does repeat what I had always thought, that the US, UK, and Canada jointly adopted Unified Thread after WWII. ( I must admit, I thought it was Unified National Thread, with C or F replacing the T for Coarse and Fine.)

Some confusion over the UN designation exists. Some people think it means Unified National based on the fact that three national entities came together to unify their thread standards; thus: Unified National Screw Thread Form. By reading the B1.1 this is not supported; rather UN is the abbreviation for UNIFIED. In the B1.1 the thread is called either Unified Inch Screw Thread or Unified Screw Thread with the preference being Unified Inch Screw Thread to indicate the unit of measure used in the screw thread series.”

I do agree with your remarks that it is bad (terrible) practice to mix screw thread types in a single product. However, I believe the UK abandoned Whitworth (for the most part) and went UNC and UNF before going metric.

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18. derekp says:

I have found a relevant statement by the British Standards Institution (BSI):

“The major sectors of British Industry were represented at a conference organised by the BSI on 23 November 1965. They gave approval to a policy statement that urged British firms to regard the traditional screw thread systems – Whitworth, BA and BSF – as obsolescent, and to make the internationally-agreed ISO metric thread as their first choice (with the ISO Inch (Unified) as second choice) for all future designs.

After many years work, the International Organisation for Standardisation (ISO) has reached agreement on ISO recommendations for general purpose screw threads. This agreement will enable the industries of the world to align the usage of screw threads and to minimise the current diversity of practice. The ISO recommendations comprise a system of ISO metric threads and a system of ISO inch threads. The ISO inch threads are the same as the existing Unified threads.”

These Unified threads are the ones agreed between Canada, the UK and the US that John Steele refers to.

It should also be said that many British companies chose to ignore this BSI advice.

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19. Ray says:

derekp and John:

You may find this article from Wikipedia of interest: http://en.wikipedia.org/wiki/Screw_thread#History_of_standardization

What is interesting was that the US, Canada and the UK actually thought and hoped that the UTS (Unified Thread Standard) would be adopted by the whole world. But, the world was going metric and by 1960 with the introduction of SI, the big switch was away from UTS to ISO metric.

UK industries resisted the switch away from Whitworth to UTS but once ISO metric was being adopted world-wide after 1960, the UK dropped Whitworth for ISO metric. Thus no one today in the UK uses UTS and if a product contains it, it is US in origin. The fact that the product is a hybrid should be the clue.

Excerpt:

Problems with lack of interchangeability among American, Canadian, and British parts during World War II led to an effort to unify the inch-based standards among these closely allied nations, and the Unified Thread Standard was adopted by the Screw Thread Standardization Committees of Canada, the United Kingdom, and the United States on November 18, 1949 in Washington, D.C., with the hope that they would be adopted universally. (The original UTS standard may be found in ASA (now ANSI) publication, Vol. 1, 1949.) UTS consists of Unified Coarse (UNC), Unified Fine (UNF), Unified Extra Fine (UNEF) and Unified Special (UNS). The standard was not widely taken up in the UK, where many companies continued to use the UK’s own British Association (BA) standard.

However, internationally, the metric system was eclipsing inch-based measurement units. In 1947, the ISO was founded; and in 1960, the metric-based International System of Units (abbreviated SI from the French Système International) was created. With continental Europe and much of the rest of the world turning to SI and the ISO metric screw thread, the UK gradually leaned in the same direction. The ISO metric screw thread is now the standard that has been adopted worldwide and has mostly displaced all former standards, including UTS. In the U.S., where UTS is still prevalent, over 40% of products contain at least some ISO metric screw threads. The UK has completely abandoned its commitment to UTS in favour of the ISO metric threads, and Canada is in between. Globalization of industries produces market pressure in favor of phasing out minority standards. A good example is the automotive industry; U.S. auto parts factories long ago developed the ability to conform to the ISO standards, and today very few parts for new cars retain inch-based sizes, regardless of being made in the U.S.

Even today, over a half century since the UTS superseded the USS and SAE series, companies still sell hardware with designations such as “USS” and “SAE” to convey that it is of inch sizes as opposed to metric. Most of this hardware is in fact made to the UTS, but the labeling and cataloging terminology is not always precise.

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20. ronniec says:

I have just found this gem in Hansard Millbank Systems.
In response to a Parliamentary question on weights and measures legislation in 1989, Francis Maude, Parliamentary Under-Secretary for Corporate Affairs, said, “There will of course be some costs in converting to the metric system. I believe, however, that the moderate nature of these proposals keeps these to a minimum.

There are also significant savings. The Institute of Production Engineers, for example, estimates the; additional cost of dual manufacture and stockholding at 3 per cent. of turnover.”. (Source: http://hansard.millbanksystems.com/commons/1989/apr/11/european-community-weights-and-measures#S6CV0150P0_19890411_HOC_367)

This is a good indication about the costs of running a dual measurement system.

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21. derekp says:

@ronniec
Thanks for drawing attention to the debate in the House of Commons in April 1989. Having read some of the MP’s contributions, for example those from Beaumont-Dark, Hamilton and Fairbairn, it occurred to me that we should be surprised, not that the metric transition has stalled, but that it has progressed as far as it has.

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