Imperial vs Metric

[Tim Britton]

I will not add to the arguments above. As an engineer, I deal almost entirely in metric measurements - and yet, having been schooled during the 50s - I still find that when estimating small distances, it is much more natural to think "that's about three inches", rather than "that's about 7.5cm". However, although I am perfectly happy in both systems, I grind my teeth when I use my favourite graphics program, Serif DrawPlus. This lets you choose either imperial measurements or metric for your drawings. But when you choose the metric scale, you find the sub-divisions are halves, quarters and eighths! Ye Gods!

Phil, I occasionally wonder at the thought process of program designers who, as you say, subdivide metric measurements with imperial references... a similar thing occurred when sheet material manufacturers were transitioning from totally imperial to totally metric dimensions and there was a period when a sheet of plywood coulkd well have one measurement in imperial and the other in metric... of course us site joiners, purely for amusement, would occasionally send a request to the stores for 3m of 4 x 2... or 6ft of 50 x 50.

 

[TRITON]

Oooooh this is a long thread.

I'll chuck in my tuppence worth.

Like many Brits I think or gauge height, length in imperial. say about 5' high, or 6' wide, but when it comes down to making such I go metric as its usually easier to sub-divide in units of 1/10/100.

 

[SteL]

As others have mentioned, I seem to vary on this depending on the size. For visualising small things - like the thickness of my wallet after checking what's new on Tooltique, I use mm. I struggle to visualise 1/8, 1/16 etc. For hand-sized to arm-sized things like my pastie that I'm just about to demolish, I think in inches. Then, things bigger than that but smaller than me I can visualise ft better, and anything a lot bigger than me I tend to go with metres. Not sure why. Maybe it is because it's easier to compare some things. I've used loads of 6" nails, so I can visualise that and I know what a 12" rule looks like. I think more people in the UK know their height in ft rather than cm/m. Must be something to do with that! If I'm drawing something out and not trying to visualise it, I'll use metric, though. What a sellout!

 

[Peri]

.........of course us site joiners, purely for amusement, would occasionally send a request to the stores for 3m of 4 x 2... or 6ft of 50 x 50.

In #126 of this thread I wrote about examples of official NASA documentation that says things like "The cross-bar is 4.82 metres long, and has 15 3/8's inch holes spaced 32mm between centres" haha

(But tbh, I wouldn't think twice about asking for 6ft of 50x50mm )

 

[Spectric]

Try to use mm as it should be easier, but at the same time a lot of stuff is manufactured using imperial and given a metric size. Sanitary ware is a good example, recently a drawing showed 83mm and you know this is really imperial at 31/4 inches because you would not design to 83mm but 80mm or 85mm. Sometimes without thinking I give a measurement as say 400mm by 9 3/8 as it fits nicely. When taking my own measurements I often end up writing it down as something like 8 1/2 + 1/16 to make sure it is too tight rather than loose, you can always skim a little more off but cannot put it back.

 

[deema]

Really?

I have a bannister 4'-10 3/8" long and want to space the 12 ballusters out equally. What's my spacing?

Whilst you're doing that, I'll divide 1483 by 13 and then go and make us both a cup of tea. You might be done by the time I'm back.

Clearly blinking shoddy workmanship using metric if you are dividing 1483 by 13. By my ruler it’s 1482.725 by 13 which gives 114.055769mm centres. Now I’d like to see that metric ruler!

I do have one that has 1/64 resolution though!

 

[Boringgeoff]

Well I just read this whole thread again because it's 34C (that's hot in F) outside and there's work to be done when it cools off.
No mention of rain gauges so far. When I was a kid in NZ we had an official rain gauge on the farm and Dad or Uncle had to read it and record the result. Measured in inches with increments of 100 points, you'd hear the old man tell our neighbour "we got 132 points overnight".
Now in retirement I've been measuring the rain for thirteen years, with a metric gauge, measures in mm. I record to the nearest .5 of a mm.
Cheers,
Geoff.

 

[jcassidy]

No, it's just that if they had mass they couldn't travel at the speed of light?

If light has no mass, how does gravity affect it???

 

[Phil Pascoe]

When taking my own measurements I often end up writing it down as something like 8 1/2 + 1/16 to make sure it is too tight rather than loose, you can always skim a little more off but cannot put it back.

I worked with a (now long dead) chippie who always said full or scant when giving a dimension so you knew on which side to err.

 

[Phil Pascoe]

In #126 of this thread I wrote about examples of official NASA documentation that says things like "The cross-bar is 4.82 metres long, and has 15 3/8's inch holes spaced 32mm between centres" haha

I worked with a chippie who would come out with gems like -
I need a piece of 3/4" ply about 18" wide and a exactly a metre long. It needs a housing cut in it, 6" from the edge 12mm wide and 3/8" deep.

 

[Cabinetman]

I worked with a chippie who would come out with gems like -
I need a piece of 3/4" ply about 18" wide and a exactly a metre long. It needs a housing cut in it, 6" from the edge 12mm wide and 3/8" deep.

Perfectly understandable Phil, just means he was bilingual like me ha ha

 

[mccpe]

If light has no mass, how does gravity affect it???

Light travels through space time which is warped by gravity. So gravity doesn’t directly act on light, as far as light is concerned, it’s going in a straight line. Gravity makes those straight lines bend.

it’s a bit early for this!

 

[Just4Fun]

I worked with a (now long dead) chippie who always said full or scant when giving a dimension so you knew on which side to err.

I worked on building sites as a part time job when I was a student and the terms there were FULL and BARE.

 

[Cabinetman]

When I write a measurement that isn’t exact say, 562 mm + or -, which means just lean the pencil one way or the other, we used to have a measurement called a knats bod.

 

[Awac]

I like imperial, I find it easier to see, 1/8th and 1/16th are usually the smallest I need. I like the brain work out when converting fractions, imperial is a little more challenging, but easy to divide in the kind of units I use. I can also remember inches easier, why, I have no idea.
I have attached the Lufkin story of measurement, I put it on another post but maybe some of you have not seen it.


A guy called Sam Doohan wrote this in Quora on the web: I have pasted some parts. I think he makes some good points. Easy division for daily life with Imperial, but metric makes sense in scientific circles.

"The imperial system is designed for people with minimal schooling and who have to think about day to day physical objects in the real world that are not easily divisible into very small fractions. We work vastly better thinking in whole numbers and we can handle much more complex mathematics when we are working from simple whole numbers".
"Base 12 is much easier for normal people handling small numbers but is far less ideal for anyone working in very large numbers.In science where we are talking about huge numbers or tiny numbers decimal helps us in thinking about things because something like 8*10 gives a round number where in base 12 it doesn’t. That’s why we changed to decimal stuff for many things, and why scientists in the US use meters and kilograms."

"You can even count on your fingers in base 12 (you count on the segments on your fingers)!"

"Don’t presume that imperial units are stupid just because you weren’t brought up to use them. There’s reasons for them and while maybe we’ve grown past the point where those reasons are all that big of a deal to us they served their purpose well for a long time. The fact that you can build battleships and fighter planes (as Britain and the US did) off the imperial system illustrates that these systems are just as accurate and effective. They are much less suited to a computerized, technologically focused world but they aren’t random or wrong; just made for a different time".

 

[eribaMotters]

I cannot understand all the faff about converting mm to fractions of an inch or vica versa and complaints about unmanageable readings.
I buy in my stock by whatever units the dealer uses and when making just use whichever lines up with my ruler or tape measure.

Colin

 

[Tim Britton]

I worked with a (now long dead) chippie who always said full or scant when giving a dimension so you knew on which side to err.

yes, that's something I recall from my time working with old guys when I was an apprentice, a measurement would be either 'scant' or 'good' to determine where to cut.

 

[Terry - Somerset]

The UK Government endorsed metrication in 1965.
In 1971 £, shillings and 240d became £ and 100p.
In 1994 gallons of petrol became litres
In 1999 a pound of potatoes became 0.453592kg

And it is still a shambolic mess - beer in pints, 8x4ft sheet material is now 2440x1220mm, speed limits are mph.

Perhaps following Brexit we should revert to imperial to sit alongside blue passports.

It only took 55 years to get close to alignment with our european friends, going in the opposite direction will, I am sure be quicker, suit us oldies, but upset the kids.

 

[pcb1962]

going in the opposite direction will, I am sure be quicker, suit us oldies, but upset the kids.

Not just the kids, I'm 58 and it would sure upset me.

 

[JoshD]

Well this is a long thread, and I speak as someone who is mostly metric, but no-one has mentioned nautical units where frankly the old units win hands down. You see a nautical mile (nm) is equal to one minute of latitude (1 minutes here is a measure of angle, 1/60 degree). And it turns out that a nautical mile is near as dammit 6000 feet. 6000 feet is a lot easier to work with than 1852m or whatever. And it gets easier still if you switch to fathoms, 1 fathom being 6 ft, so a nautical mile is 1000 fathoms.

So here you have a system of units that links the human size to that of the planet.

For example, I know that

* the circumference of the earth is 360*60=21,600nm.
* If I am at latitude 50° 12.345' N and you are at 50° 12.346' on the same longitude then we are 1/1000 of a nautical mile apart, ie 1 fathom or 6 feet.
* If I coil my ropes so that each turn is from outstretched hand to outstretched hand, pretty much a fathom for most people, then the counting the coils of a stored rope gives me its length in fathoms.

A cable is 1/10 nm, ie 600ft or 100 fathoms; on my boat that's about 16 boats lengths.