Imperial v Metric Measures

[Brian GParticipant @briang]

I'll be honest, I'll happily switch between units depending on specifications, drawings or materials and to me 10' is about 2" over 3m. I have no problem with railways being measured in chains, within the railway industry it is an established and internally consistent unit and any attempt to change it would almost certainly be expensive and prone to (potentially catastrophic) errors during the transition period. On the other hand, I had no hope of guessing how long 2,300' is whilst 700m or 35 cricket pitches (chains) is easy to picture.

I fail to see why anybody would consider the imperial/customary system simpler or more natural. To switch from mm to m to km is just a matter of moving the decimal 3 places between units, whilst to go from inches to feet, to yards chains, furlongs and miles requires a number of sometimes complex divisions.

Consider the difference in gauge between the Iberian railways 5' 5 21/32" and the rest of Europe's 4' 8 1/2" standard gauge. To convert in imperial/US customary units it is necessary to either carry out calculations in three different units and somehow merge them together or convert everything to the lowest common denominator. In the metric system it is just a matter of 1.668 – 1.435. An engineer designing variable gauge wheelsets would find it far easier in metric than adding the further complication of converting the final 5/32" to thou.

Brian G

[PatJParticipant @patj87806]

Posted by Martin Connelly on 09/04/2022 07:57:33:

PatJ, having worked in engineering all my working life I am used to working with metric and imperial measurements. I had to convert 40'-4" into metres in my head to visualise it. 40' is 12m (more or less) as there are 40" to the metre (more or less) and then 4" is 100mm or 0.1m. So you are talking about 12.1m. This is what the majority of the world will do as the idea that "Everyone knows what 40 feet is" is clearly wrong and very USAcentric.

Martin C

I think Martin hits the nail on the head.

I should say "Everybody around these parts…..".

I have heard that many outside the US can look at metric dimensions and immediately know that 7,426 mm is something they can envision. I suppose it is like learning a language (math is just a foreign language really), the language you learn first becomes the one that seems natural.

We did a couple of German steel plant designs in the mid-south, and we all had to get German dictionaries and learn German, in order to read the machine drawings, plus all the German drawings were in metric, so all that had to be converted.

We just don't build stuff in metric here, and people don't generally think in metric either, at least not in the building trade. They tried to convert us in school, but it never took off.

Inches/feet/yards/miles is just too convenient in the building/industrial construction market.

I do see more and more machinery being built in the US in metric, but I am pretty sure the building industry will never go metric here; it is too entrenched.

Interestingly, I have both an Architect's scale, and an Engineer's scale, and the Architect's scale measures feet and inches, and the Engineer's scale measures feet in tenths.

My drawings are normally made using an Engineer's scale, not necessarily an Architect's scale, unless it is a building plan or something, and I am more comfortable with measuring things in decimal than using Architectural nomenclature.

And on a totally unrelated topic, I ran into a Brit who is a member of the local running club.

We have a running series where thousands of people run 10 races total, starting with two 5K's, then two 5 miles, and finally ending with two 1/2 marathons.

We were chatting, and I asked him "Did you run these in GB?", and he said "No, we don't have these in GB".

He was a really nice fellow, and a good runner too. I could never keep up with him.

He was thrilled to be running with so many people; men and women, at 7:00 A.M. every Sunday.
Its a big thing around here.

 

Edited By PatJ on 09/04/2022 10:43:37

[Dave HalfordParticipant @davehalford22513]

Posted by PatJ on 09/04/2022 03:22:51:

I work in the design/building industry in the States, and everything is feet and inches, although some components are designed and measured in metric, such as 3D modeled equipment.

Generally if metric is on the drawings, it is in inches/metric.

I had a question about the power line right of way extending over too close to a new building being constructed.

I measured from the power line pole to the building, and it was 40'-4".

Everyone knows what 40 feet is, and everyone knows how wide a 10' wide easment is.

Nobody would ever say "That building is 7,680 1/8ths of an inch off of that power pole.

Nobody would know what the heck that represents.

Breaking down the units into an impossbily small unit such as the mm is counterproductive in the construction world.

I am working on a lagoon that is 2,300 feet long.

Again, nobody would have any idea how big that is in metric.

Feet and inches is very convenient, usable, functional, and immediately understood any anyone in the building industry.

The metric-pushers don't have to build buildings and stuff is my guess, else they would revolt.

.

We used to think like that over here, but in the end it doesn't matter, 30mm is a foot and a metre is 3foot 3 inch.

I just wish my 2014 Jeep knew it lives in the world of the big gallon now, the MPG is literally miles off.

Edited By Dave Halford on 09/04/2022 10:42:47

[PatJParticipant @patj87806]

It is annoying to have to own two sets of tools; ie: wrenches, allen wrenches, sockets, etc., since autos are exclusively metric now, but the old engines I work on are definitely not metric.

Makes for a very heavy tool bag.

.

[Nicholas FarrParticipant @nicholasfarr14254]

Posted by DMB on 08/04/2022 21:54:43:

Just as crazy, new car, 17ft long is described as being 5181.6mm. I can more or less visualise 17ft but not that ridiculous quantity of mm.

About the limit in mm is 600, generally used to describe the depth of kitchen worktops. Why not 60cm?

I would have thought that metres would be best size unit for a car's length and perhaps, call me 178cm, not 1.78m tall.

Edited By DMB on 08/04/2022 21:58:24

Hi DMB, as has been said, in engineering using meters & mm's are the norm. When I was working and had to cut and make many large fabricated items, having lengths like 5181.6mm was easier to read and mark out than 2.1816M, simple reason is that the thousand unit is full meters and the hundreds, tens and single units can simply be read off directly from the tape measure after the 5M point and you don't have to think about working it all out, and I have had to cut metal to 0.5mm over that sort of length, but not always and anything less the 1mm can often be ignored. As been pointed out, 1M is roughly 40 inch's, so it shouldn't be too hard to covert these to visualize the size of something into feet and inch's.

Regards Nick.

[Mick B1Participant @mickb1]

Posted by PatJ on 09/04/2022 03:22:51:

…

I am working on a lagoon that is 2,300 feet long.

Again, nobody would have any idea how big that is in metric.

…

Well it's water, so that's a bit over 3 3/4 cables (Admiralty – Imperial).

Ah – wait, but you're in America, so it's about 3.19 of your cables…

[Howard LewisParticipant @howardlewis46836]

At CAV, because of tghe original licence to manufactire Bosch products under licence, the standard units for measurement were Metric.

But I was involved in developing another product, which being American was to Imperial, and Unified standars.

So we had drawings calling for parts to be 6.354 mm diameter.

So we often worked in both systems, (for odd fixtures, sometimes in both )

And my toolkit included Whitworth spanners as well as A/F and Metric!

In essence, the units are a measurement of an object. The one to use is that which is most convenient.

In photographic film, speeds (sensitivities ) were derived by different methods and so measured in different units &nbsp

So there were Hurter and Driffield, Weston, Scheiner, Gost, BS and ASA. film speeds

All applicable to the same material.

Merely a different unit for the same thing.

You will be just as tired after walking 50 Kilometres as if you had walked 30 UK miles

The wood occupies the same space whether it is 8 feet long, or 24438,4 mm long, and you are going to cut bit anyway, in most cases.

You just need to make the raw material large enough that it can made to the required size..

Howard

[Nicholas FarrParticipant @nicholasfarr14254]

Posted by Howard Lewis on 09/04/2022 11:15:51:

snip

You just need to make the raw material large enough that it can made to the required size..

Howard

Hi Howard, or would that be small enough.

Regards Nick.

[Howard LewisParticipant @howardlewis46836]

Yes, Nicholas, no point in wasting good material.

That just inflates the cost and time to produce the end product.

Howard

[peak4Participant @peak4]

I know I've posted this before, but it's still worth a re-read of "Which Inch" 6 pages
http://metricationmatters.com/docs/WhichInch.pdf

There's a rather longer treatise here; "A chronological history of the modern metric system (to 2008)" 142 pages
http://www.metricationmatters.com/docs/MetricationTimeline.pdf

Now don't get me started on the volume of a gallon.

Bill

[V8EngParticipant @v8eng]

30mm is a foot

 

Edited By Dave Halford on 09/04/2022 10:42:47

Were you the bloke who parked next to me on that basis last week?

Edited By V8Eng on 09/04/2022 11:54:41

Edited By V8Eng on 09/04/2022 11:59:58

[V8EngParticipant @v8eng]

Posted by David Davies 8 on 09/04/2022 10:25:19:

Centimetres belong with dressmakers and schoolteachers. Engineers use metres and millimetres. Similarly radius is a concept used by mathematics teachers and turners. Engineers use diameter, —— Discuss.

Dave……tongue in cheek!

Do not tell the Furniture trade and Estate Agents that!

[Dave HalfordParticipant @davehalford22513]

Posted by V8Eng on 09/04/2022 11:52:41:

30mm is a foot

Edited By Dave Halford on 09/04/2022 10:42:47

Were you the bloke who parked next to me on that basis last week?

Edited By V8Eng on 09/04/2022 11:54:41

Edited By V8Eng on 09/04/2022 11:59:58

Very likely it was

[Marischal EllisParticipant @marischalellis28661]

I still refer to pairs (prs) of hinges or 1 1/2 prs, 2 pair (s), and so on. Was /is standard in the building industry…..when I was young! Hinges come and fit in twos well nearly! So contract could have say 200++++prs (400+++) + of hinges, etc. Were sold in pairs, so a half pair = one.

My introduction to metric was my first technical exam,………I was told by a lecturer……'its easy, remember one inch equals 25.4 mm'……….. as I walked through the door of the exam room. I passed but questioned every exam thereafter! I also remember not being handed out log tables, formulas, and other hand outs as part of the info made available. I questioned the adjudicator (all listed on the exam paper) and was told…..' its too late you will just have to get on'…..a riot arose the exam room….panic for adjudicator. Passed it but it would have meant a complete failure and the sack from work.

Just shows the standard of the adjudicators and they couldn't sitting the exam. Happy days…no it wasn't. Best wishes to all.

[CalumParticipant @calumgalleitch87969]

Posted by PatJ on 09/04/2022 03:22:51:

The metric-pushers don't have to build buildings and stuff is my guess, else they would revolt.

Completely correct, we haven't built anything here in Europe since the French Revolution. Every we time we start digging a foundation we get confused and have to go on strike.

[Mick B1Participant @mickb1]

Posted by David Davies 8 on 09/04/2022 10:25:19:

Centimetres belong with dressmakers and schoolteachers. Engineers use metres and millimetres. Similarly radius is a concept used by mathematics teachers and turners. Engineers use diameter, —— Discuss.

Dave……tongue in cheek!

When dimensioning a convex or concave curved profile on a component, radius is certainly a legitimate engineering definition. When I was a tooling designer I'd use it freely in drawings whenever appropriate, as did every other designer whose work I ever saw.

[Nick WheelerParticipant @nickwheeler]

Perhaps Dave was using the modern definition of engineer, which seems to be somebody with a bent screwdriver and a hammer who can't fix your washing machine.

[Anonymous]

Posted by John Haine on 09/04/2022 10:11:58:

Please could we BAN any further discussion about metric v Imperial units. It's boring and wastes everyone's time.

Lots of things wrong with that.

– it's eminently clear what this thread is about so why are you even here?

– it's obviously not boring/time-wasting for the other participants here.

– who are you to decide what I should or should not be interested and spend my time on?

…. your post is a wind-up, right?

[not done it yetParticipant @notdoneityet]

To be sensible, the unit ‘H’ does not mean ‘hour’. An hour is ‘h’ – H is the Henry. Get it right.

The lagoon was clearly 700m long, rounded off to 2300ft by someone.

Don’t you just hate it when approximate values (metric or imperial) are converted to an exact value, to several significant figures, in the other system. Idiots doing the conversions. Probably mostly stupid journalists?

There are a lot of ‘idle uniteers’ around. Often they quote MW instead of MWh, so one has to guess whether they are referring to power or energy.

Beekeepers are the same. Few know what a ‘super’ is really. They have never learned any Latin, obviously.

Same with cells and batteries. Was there ever an anti-aircraft battery with only one gun? – no batteries are groups of more than one cell!

Apparently the americans missed Mars with a spacecraft, because someone didn’t use the correct conversion. I often use the wrong case on purpose, btw.

[Howard LewisParticipant @howardlewis46836]

This argument is about units.

For some time there have been preferred standards for Metric units, and cms, although nuseful in certain circumstances are less preferred that mm and metres.

But at the end the argument is about what unit should be used.

That depends on the size of the feature being measured.

Unless you like LOTS of Zeroes before or after the decimal point, you would not quote the distance between Earth and the Sun in microns, any more than the clearance between a shaft and the bearing in which it runs in light years!

Clamping two large items together I might use M12 x 1.75, but if I wanted a fine adjustment more likely 1/2" UNEF or even ME 40.

Imperial Micrometers use 40 tpoi thread beacsue it is better suited to task inn hand than a M12 x 1.75 thread.

You will have a job refurbishing a 1910 Drummond using Metric hardware, just as if you tried to rebuild a damaged 2018 car using BSW hardware.

The unit has to be suitable for the task in hand, in the same way as the tool or machine being used.

No point bin going to war over which breed of horse to enter in the Grand national or for ploughing. Each type is ideal for a particular purpose.

There must be more important things with which to occupy our time

Howard

[Chris TriceParticipant @christrice43267]

Metric is the rightful heir to the throne and already used in every progressive country and culture. Units of dimension are linked to volume, weights and indirectly temperature, and universally adopted by all the sciences. Based on decimals, the maths is a lot easier too. I work happily in imperial but once "our" generation dies out, the world will be metric rather than clinging to archaic and arbitrary measurements based (allegedly) on nothing more than the length between a 16th century monarch's finger tip and his nose. It's a done deal so don't shoot the messenger. As a bit of interesting trivia, an English bishop, John Wilkins, (1614-1672) invented the concept of a universal integrated measuring system that was the foundation of the metric system. The only people keeping imperial alive is the model engineer.

[Tony Pratt 1Participant @tonypratt1]

Oh no not yet another pointless thread on Imperial v Metric Measures

Tony

[Martin KyteParticipant @martinkyte99762]

Posted by Chris Trice on 09/04/2022 18:19:20:

The only people keeping imperial alive is the model engineer.

And that little thing called back compatability.

regards Martin

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Martin Kyte on 09/04/2022 19:43:13:

Posted by Chris Trice on 09/04/2022 18:19:20:

The only people keeping imperial alive is the model engineer.

And that little thing called back compatability.

regards Martin

.

Like making DIL chips and boards with 2.54mm pitch

ferinstance

MichaelG.

[Simon Williams 3Participant @simonwilliams3]

Count your blessings chaps.

Having three systems of measurement gives me a cast iron (well, chrome vanadium actually) reason why I have to have THREE sets of shiny new spanners. Three sets gotta be more fun than just one, eh?

edit for minor typo

Edited By Simon Williams 3 on 09/04/2022 20:10:03

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