Metric vs Imperial – Practical or Traditional?

[Ian AbbottParticipant @ianabbott31222]

I believe that my 90 year old Randa lathe was built to the old Stephenson “that’s about right” standard, as in standard gauge railways.

 

Ian 

[its-smeeParticipant @its-smee]

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[mgjParticipant @mgj]

Am I not right in saying that the metric pipe thread is actually BSP? Many metric cars actually use 3/8 UNF on brake fittings.

 

And the dairy and food industries, who sell their products in grammes and kg,while using a few SMS and DIN fittings, mainly use RJT. Which are imperial.

 

And the US who still use some imperial (but different in some respects from ours) have a military who have metricated. 

 

When you buy a car, do you want to know how many kw it has, or do we not all think proper horsepower. Thats decent SAE BHP horsepower, not some DIN european fakery type rubbish. 

 

There is no more logic in metric than imperial surely? Things happen per unit distance by unit time/area etc or whatever.  People argue that with all to the base 10 its easier. That is so on hte face of it, but start converting from kg to newtons, or using gas laws and constants, or aerodynamic functions. In no time at all you are into “illogical” figures, simply because the physical world is like that. Nowadays with computers or calculators, whether you multiply by 9.81 or 32.2 is really of no consequence.

 

People argue about dropping the decimal point somewhere with metric -well yesssss. but then the lbs to lbs force and back is to me a lot more dodgy.

 

So doing engineering calculations I prefer to work in metric.

 

And when munching metal I think in thous and inches. And mostly use metric fasteners for convenience, and metric drills too.

 

 

Who cares- at the end of the day its only a figure on a dial, either way.

 

As for tooling in inch sizes – well there is a lot of stuff that uses them. No one will change a system of tool holders for some CNC machines. Nor will I buy 6mm tool steel, when all my little holders are 1/4″. So hopefully good christian units will be around for a long time to come. 

 

Then we can all use what we want

 

 

Edited By meyrick griffith-jones on 18/08/2009 18:11:20

Edited By meyrick griffith-jones on 18/08/2009 18:18:44

Edited By meyrick griffith-jones on 18/08/2009 18:20:09

[CirclipParticipant @circlip]

Ahh, but it doesn’t seem as much to stick 2P on a litre as 10P on a Gallon

[mgjParticipant @mgj]

More like £4.50, and that, even to this bunch of tax hiking, pension grabbing fiends is £4/10/0d which  they ain’t earned but don’t stop them spending.

[Peter TuckerParticipant @petertucker86088]

Paul Atkin,

I cannot answer your question, and I would say from the posts recived no one else can, however I would think if someone was to build an exact model they would work in the units used on the original.

So far as metric V imperial if you completly reject one system then, in my opinion your missing out on half the game, one example studding in aluminum needs a robust thread Witworth is a better choise than metric.  Another point to remember is the metric system was created in the laboritory by one man (and the lab is where it works best), where as the imperial system was made piecemeal by workers in “the field” there for is a more practical working system.  I am an excarpenter who trained in imperial but worked most years in metric, my imperial rule had 1/10ths”, 1/12ths”, and 1/16ths” all biger and easier to read than mms but between them (the inch fractions) giving a finer presision of mesurment.

 

We have a multitude of standards ( all usefull in their own way) why not embrace them all.

 

Peter

[Paul AtkinParticipant @paulatkin73780]

Meyrick,

Yes as I mentioned in my opening post – most industrial pipe sizes are still in inches.

 

Peter,

Maybe its just me and the fact that I live overseas which causes me to be more sensitive to the variations.  I hate the fact that there are so many different standards.  Its simply not efficient or convenient and must cost industry billions of pounds per day on a global scale.

 

Its not only metric vs imperial, there are deg Celsius vs Fahrenheit (why does the BBC still quote degF??), differing TV systems, NTSC vs PAL, different voltages and frequencies, different connectors for a mutlitude of electrical devices, incompatible computer software, proprietary designs such as memory cards for digital cameras, region coding for DVD’s, BluRay vs HDDVD, Shoe sizing, Imperial gallons vs US gallons…….. ARRGGHHHH Rant! Rant! Rant!

 

If I am thinking only about modelling then the fact that I could buy one metric set of drills, taps and dies is surely far more efficient than having to buy 2 of everything (or more if you start considering whitworth, BA etc).  And then there’s storage space which is at a premium for any but the luckiest of modelllers.  I have a multi drawer case with all my metric cap heads, nuts, washers, spring washers in from 2mm up to 10mm all arranged in spearate drawers.  I would need to at least double or treble my storage capacity to work with even one or two of the other “standards”, and that’s only one simple example.

 

And one more point Peter, however the metric system was developed, it cannot be worse than using 3 grains of barleycorn to set the “standard” inch. http://en.wikipedia.org/wiki/Inch

 

Please excuse me,  I just get so annoyed by the sheer inconvenience of it all……….

[Peter TuckerParticipant @petertucker86088]

Paul.

I cant disagree with any thing you have said however the alternatives would be worse, i.e. either no standards as screw threads before Witworth, or the entire species excepting only one standard Witworth, only no metric anything.  As for 3 grains of barleycorn to set the “standard” inch, the acuracy to which standard measures are set has advanced with the need and ability of presison, the same has hapened with metric just not from such antiquated beginings.

The thing that I find frustrating is the mediocre tends to dominate for instance windoz on PCs and VHS over Beta with vidios,  but thats another entirly difrent rant..  Sorry!!

 

Peter.

[Ian S CParticipant @iansc]

I believe that the official standard measure in the USA is a one Metre sample held by the national standards organization.IAN.S.C.

[mgjParticipant @mgj]

Ah well – once you have that metric changewheel, you got it made!!!!!

 

BUT – have you seen a metric thread dial indicator – 3 different pinons, and however many lines and a whole darned chart, just for a few mouldy European threads. 

 

I rather like the 4 line Imperial job. Any line for multiples of the leadscrew, and opposite pairs for even numbers. Not bad for an illogical system.

[Ian AbbottParticipant @ianabbott31222]

Hey Ian SC,

 

The States don’t use the metre, they have something called the meter, which I believe is similar and used by the US auto industry.

 

And, I’ve just seen the best yet, rail standard gauge (gage in the US) is now 1,440mm. 

 

Ian

[russellParticipant @russell]

i was surprised the other night when leafing through an old ME (1904, well past its centenary!) to see the first constructional item was imperial (fractions), the next was in millimeters.  

Seems this battle has now overtaken the 100year war….

 

russell 

[Ian S CParticipant @iansc]

Our rail gauge here is still 3’6″and I think itwill stay that way,even if imperial completely disappears from NZ.IAN S.C

[MikeParticipant @mike89748]

I spent all my working life in the publishing industry, and used to design newspaper pages using another Imperial measurement – ems and points (72 points to an inch, I recall). When the industry changed to the metric standard, I remember going to our suppliers and asking for “a metric ruler about two feet long, please.” Points, of course, still survive in the height of computer typefaces. Surprising the “metricate everything” mob haven’t got their sticky fingers on that.

Even after more than 30 years working to metric standards, I still think in Imperial. Just an old fogey, maybe!

[TerrydParticipant @terryd72465]

Bricks Are metric.  215 x 65 x 102.5  (see BS 3921).  That gives a coordinating size in a wall of 225 x 75.  The latter dimension of 102.5 is not a conversion from imperial, but because the width of a brick has to coordinate with the length in certain bonds.  So two widths plus two mortar joints of 10 mm is equal to one full brick with one joint of 10 mm, i.e. 225mm.  Thus the bricks can coordinate.  If you doubt the difference between Metric and imperial bricks I suggest you try matching the two in a sectionof brickwork.  Also slabs ARE 300 x 600. 

 

As a mid 60 year old I am extremely happy with the metric system and prefer it.  we can all find fault with all systems such as ‘try dividing by three’ just try multiplying fractional sizes without converting or dividing decimal imperial by three – no significant difference.  A serious problem with imperial measures is that they were not constant across the world, there were no agreed standards.  Try getting an English quart into an American quart pot. There are also many definitions of a mile, there is no standard.

 

Frank Hornby used imperial in the late 19th century when inventing Meccano, as one would expect but was specifying grammes (sic) for his weighing experiments.

 

Please could we also bury this insistence on blaming this vague concept of ‘Europe’ for metrication it was the British government who decided to adopt the more logical metric system well before ‘Europe’ was involved with such decisions.  It was made on the recommendation of British scientists, engineers and other interested parties who wanted to be rid of the haphazard, complex and illogical system that is the imperial one and use a simple straightforward system with one length measurement and one volumetric and weight measure.  ( the decimetre, hectolitre etc are made up measures and are not part of the ISO system).

 

By the way, we use the L as the basis of the pound sterling (&#163 because it is derived from a French denomination, the Livre, Our system of weights are based on a medieval French system Hence ‘lbs’ for pound and the avoirdupois ounce etc.  in fact it was the influence of European countries who gave us the Imperial system and they dumped it when a better system came along.  Another by the way, those who think that the inch was the width of Henry the Eighths thumb, just remember he was a Tudor – Welsh / Normans.

[Paul HansonParticipant @paulhanson23918]

This a fascinating debate.  I want to make an observation as someone fairly new to the hobby.

 

All of the comments are talking about the present (and the past!) – no one has mentioned the future.

 

How do we attract more people into the hobby? People like myself who are of a generation only schooled on Metric. People like myself with no previous engineering background. I fully appreciate those with a traditional frame of mind – their wisdom and practical experience has been invaluable to a newbie like me. But I have to say when I got into this area I was mortified at how much imperial was still around. I am not commenting on which system is best but where the future is.

 

I am not saying that Model Eng should try to become hip and nintendo friendly (turbo cad for the DS anyone?) but if we carry on like this it’s a dying art.

[David Clark 13Participant @davidclark13]

Hi There

Metric and imperial will continue to be used side by side for many years to come.

Anyone who can build a locomotive or similar and get it working should have no trouble converting between the two systems.

regards David

 

[John Wood1Participant @johnwood1]

Well said David, I think that about sums up the debate. I shall certainly avoid any comment but will just keep my head down and enjoy the versatility of using both systems when required in my own workshop.

 

Keep turning

John

[DMBParticipant @dmb]

I also suffered being taught irrelevant historical measurments like rods poles perches.

Also, decimetres hectometres and so on. Then there was our historic money  with farthings threpenny-joeies, guineas, tanners and so on.

How much easier is the new currency to add, divide and multiply.

The same goes for metric e.g.,  we seem to be using only mm, cm and M, having apparently cut out all the in – between ones like decimetres. Pity 600mm has to be used for kitchen cupboards instead of .6M  Its all about visualising, like Ian said 18,288mm. Why not  make it simpler by saying 18.288M then mentally add on another 10% (1 .8) and you have near enough, 20 (yards!) I am making a Harold Hall design to his metric drawing which uses piece of metal 70 mm long; no prob. visualising this. Equally, I can look for a piece of stock thats around 3 ins. long for it. Most people have digi-calipers and/or DROs, so whats prob? Just seems like something to moan about.

John 

Edited By John Coleman 1 on 11/11/2009 12:00:07

[Martin WParticipant @martinw]

Hi All

 

I think what this extensive thread shows that we are all capable of handling numbers and measurements whatever their origin but the real problem is CHANGE. As a species it seems that we humans love what we get accustomed to, even if we dislike it at the time, and resist changes to that system.

 

In the computer world there are/were several ways of expressing numbers, binary, octal and hexadecimal just to mention three, oops here come the thirds again, but there was little argument about using them as they were, relatively speaking, new standards and in them days people were used to them all.

 

I reckon variety is the spice of life and this thread has surely shown that, so not sure which is best then press the conversion button on your vernier/calculator and use the easiest for you. What the hell it’s only how far two points are apart physically.

 

Cheers

 

 

Martin

[Peter G. ShawParticipant @peterg-shaw75338]

I too was brought up on imperial. Indeed when studying Telecomms Principles we were still using cgs units which eventually became mks.

 

For myself, I decided one year that a kitchen cabinet I was making would be done completely in metric – which was how I changed over as it were. Later, I bought an imperial micrometer (for use on a Maxi engine). Then later again when I got involved in engineering I decided that I would only use metric equipment.

 

Ok, I do have imperial drills, but have decided to go totally metric so as they break/wear out, they will not be replaced.

 

These days, I now automatically think mostly in metric, but can still use imperial – indeed, if measuring something I use whichever system has the nearest graduation mark.

 

Like other people, I don’t see it as a problem, after all conversion is easy. What I would suggest though, is that anyone starting from new in this hobby possibly needs to consider going totally metric as certainly in the UK, everything else is slowly going that way.

 

Finally, a comical story.

 

About 15 years ago I wanted to build a porch and so I contacted the local planning department. Very helpful except And she kept saying it. Fair enough, I was quite happy and it was easy for me to do.

 

Then, one day, whilst discussing something, it happened!

 

LP: “Of course, we’re not really bothered about the odd inch or two.”

Bit of quiet, then-

ME: “Er, excuse me. What are these inches you have just mentioned?”

Dead Silence, then I slowly burst out laughing.

 

After that, we got on just fine.

 

Regards,

 

Peter G. Shaw

[Vapeur89Participant @vapeur89]

I’m on the metric side of the hobby and I use either metric or imperial drawings or kits.  I have no problems with that. It does’nt take very long to convert from imperial to metric. The reverse is not true if you have to work with imperial fractional. You can download a free professional unit converter at http://www.katmarsoftware.com/uconeer.htm

 As to what represents a distance… it’s not easier to figure 1 53/64’’ than 46,434 mm.

 Many times I order stock bars from bristish suppliers as it is a cheaper than in France.

To deal with imperial drawings I use exclusively metric holes and metric thread and I convert distances in mm with three decimals.

In fact before making chips we have to  study and dig into the drawing to understand or to adapt the stock bar we have on hand or to deal with a limited set of tools. So converting is a good starter.

The strengh of SI unit system clearly appears when you have to work with complex physics formulas, but as long as only length is concerned why worry about that?

[Ian AbbottParticipant @ianabbott31222]

Thinking back to the old pounds, shillings and pence etc., we used to make money out of American tourists who couldn’t handle the exchange.  I thought that those days had passed, but when I was living on the West Coast of Canada, we had a lot of American tourists and they couldn’t do the conversion from US to Canadian dollars either.

Now this seems strange, as it’s just a matter of percentage, metric again, but on thinking about it, the problem, it’s that the school system there in the US, as over here in the UK and in Canada is now crap.

 

How is it that we were thrown out of school aged 15 and on to college, with a complete knowledge of ten different types of measurement and a wide vocabulary, but in the current western “civilization”, schools turn out young adults at 18 who can’t spell (even with a spellcheck) and can barely count to ten?

 

Feeling curmudgeonly tonight.

 

Ian 

[CirclipParticipant @circlip]

You dissin the well good bro’s??   Innit

[Ian AbbottParticipant @ianabbott31222]

Sorry, it’s just too easy, like making fun of Gordon Brown…..

 

Still curmudgeonly.

 

Ian 

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