Thread: Metric Vs Imperial

G'day All.
Working in a sawmill as I do, We use both.
Eg: 4x4 1/3.6
4x2 12/2.7 etc etc etc .
At home I use both.
for fine work it is mm
for longer work it is feet & inches with mm.
Eg: 7'5" + 17mm.

Have yet to have a bad measuring f#ckup.

Hooroo.
Regards, Trevor
Grafton

Note my age! I use both and like most posters find metric much easier if you have to do any arithmetic. I remember being taught how to add/subtract/multiply and divide fractions but I can't remember when I last did it.
I generally use tapes etc. that have both (although the wrong edge problem is a curse) but I frequently find it easier to read the imperial side when having to read at a distance or at an awkward angle. The figures tend to be bigger!
Agree that metres and millimetres are the only things to use. Never centimetres. They are for dressmakers! (They have to buy 2 metres of 42 inch material which seems better than 2.7 metres of 2x3) Who remembers decametres!
Cheers

Millimetres for woodworkers,centremeters for dressmakers. Give me a left handed metric tape anyday(for woodwork)of course.

OK, I think the main reason for stuff ups with Metric tapes is the poor marking system - it is for me. The Imperial rules seem to have a secondary and often tertiary set of markings - black inches, then red feet printed next to the inches, and sometimes they have a total inches marking as well.

I find I tend to slip 100mm relatively easily, so I mark twice - this also catches the eye trick of hitting the wrong 1 cm major tick mark - the square won't line up so I get a warning that something is wrong.

As for the 'rest of the world is metric' arguement - HA! Double HA! - MauserWerk is Imperial ( a friend spent 3 months doing a 'post-graduate' in firearms fitting there), and if you look around you can find rulers marked '1 Zoll = 25.4mm' - intended for the Austrian or German markets. I often find French internet sites with Pieds and Pounds - the Metric stuff is for 'Government work', a fair part of the population still use a bastard Imperial or other traditional local system of measurements.

Just like the Euro-sausage and Euro-beer, the local product is more human-friendly. Remember this when you string your bow - the distance from the string at rest to the back of the grip is a fistmele. At least we gave up on the cubit & ell.

Originally Posted by bsrlee

As for the 'rest of the world is metric' arguement - HA! Double HA! - MauserWerk is Imperial ( a friend spent 3 months doing a 'post-graduate' in firearms fitting there), and if you look around you can find rulers marked '1 Zoll = 25.4mm' - intended for the Austrian or German markets. I often find French internet sites with Pieds and Pounds - the Metric stuff is for 'Government work', a fair part of the population still use a bastard Imperial or other traditional local system of measurements.

I too found it "unusual" when DIYing in Bavaria and found all the water piping to be British imperial and they were several years behind UK in providing connector adaptors for 1/2" to 15mm for instance. The steel water piping and threads are still imperial and Whitworth threads are the norm on a lot of fittings. I don’t think it will ever completely unify because of the vast number of legacy installations.

The metric system has one major fault. By definition, each metric unit is greater or less than the next by a factor of 10. That is just too large a step. It explains the ease of making mistakes when measuring in metric.

There is a good scientific reason for the problem and Derek touched on it earlier. The human brain cannot instantly recognise quantities greater than three or four.

For example, imagine you're a prehistoric hunter and you bring back the day's catch of rabbits, lizards, or whatever and proudly drop them on the cave floor for SWMBO's inspection.

If there's two or three, she'll recognize the total instantly, belt you over the ear and send you back out to get more for the cave-kids. If there's four or five, it will take a fraction of a second for her to recognise how many there are. You might just have time to duck. If there's six or seven, she'll have to mentally count them. If there's nine or ten, she'll definitely have to take off her thongs and tick them off on her pinkies.

This is the prime reason for difficulty in visualising metric sizes and distances. For example, can you visualise the height of someone 183cm tall as distinct from 182cm or 173cm? It is easy to make a mistake of 1 or 10 because metric units are large in relation to sub-units. Changing from cm to decimetres or metres doesn't help. Then you're comparing 18.3 against 18.2 and 17.3 or 1.83 against 1.82 and 1.73. Increments of 10 are just too big.

So how can imperial be any easier? Because one can always break imperial units into sub-units of no more than four. Ah, you say, how can that be when there are twelve inches in a foot? Easy! Those of us who grew up with imperial have developed the habit of instantly and effortlessly visualising feet as made up of 4 lots of 3 inches or 3 lots of 4 inches or two lots of 6 inches. We think of a yard as 3 units of a foot or 4 lots of 9 inches. Nine inches, of course, is three lots of 3 inches. Six inches can be two lots of 3 inches or 3 lots of 2 inches or 4 lots of 1 and a half inches. Lovely! Makes it easy to space things equally whether dividing by 2, 3 or 4.

Now, what's a metre divided by three? Oh! 33.333cm or 333.33 mm. Won't find that mark on your metric rule, will you darl?

Of course, imperial gets tougher when you have to divide by 5 or 10. That's when the 1/10th of an inch ruler divisions come into play and we switch to a mixture of decimal and imperial, e.g. 2' or 24" divided by 5 becomes 4.8 inches.

For measurements in fractions of an inch, as Derek indicated, those who think in imperial regard inches as consisting of 2 x 1/2" or 4 x 1/4". Those units are broken down into 1/8", 1/16", 1/32" and 1/64" but never dividing by more than 4. That is why it is easier to spot a mistake in imperial - because you can instantly recognise quantities or divisions of 4 or less
and are less likely to be out by one, let alone by ten.

And now, since its past this caveman's bedtime, the defence rests! Its over to the prosecution.

regards
Coldamus

Coldamus

I totally and utterly agree. You put it far, far better than I.

Regards from Perth

Derek

For example, can you visualise the height of someone 183cm tall as distinct from 182cm or 173cm?

I have no problems visualising peoples height in metric. It is really simple and it is exactly what I do in imperial.

180cm is sort of average
190cm is kind of tall
200cm is really tall
170cm is kind of short

A little under 6" is average
6'4" is kind of tall
etc.

Those of us who grew up with imperial have developed the habit of instantly and effortlessly visualising feet as made up of 4 lots of 3 inches or 3 lots of 4 inches or two lots of 6 inches

Did you just make this up? I grew up with imperial and don't do this. I think of a foot as been about a 'that' long. I can spread my hands to be about a foot apart without thinking. Oddly, I can do this in metric too, 300mm.

Now, what's a metre divided by three? Oh! 33.333cm or 333.33 mm. Won't find that mark on your metric rule, will you darl?

This is a little spurious. You are quite right if I make something a meter high and want to put dividers two dividers at equal distance I'd use 333mm and at 666mm and I'll be out by .3 of a mm. I could have made it 900mm high instead and not had an issue. And there is no mark on the ruler for those. However, if I was 32", I firstly have to workout what a third of that is. It is 10.66" or 10 2/3". Both my rulers have imperial on one side and both of them are marked in 16ths of an inch. It is sort of 10 and almost 11/16ths of an inch. There isn't a mark on the ruler for that.

The only problem I can see with metic is the some of the damned ruler makers don't make the 5mm marks standout. Get a ruler that does and your life will be complete.

Originally Posted by Coldamus

The human brain cannot instantly recognise quantities greater than three or four.

regards
Coldamus

I can instantly tell the difference between four 1 dollar coins and four ten dollar notes.

The comment about the Americans use of the system is right. Some little while ago, I was on another forum and using a large paddle stirred things up on the question of metric and imperial - there was an minor explosion.
I don't think Neil will mind if I insert the following link for those who are interested in the American reaction to this topic.

Link

Cheers

Originally Posted by Coldamus

........ the defence rests!

This jury finds you guilty is speaking complete and utter rubbish.

Peter.

Originally Posted by Grunt

Did you just make this up? I grew up with imperial and don't do this. I think of a foot as been about a 'that' long.

No, but I did not express it very well. I did not mean that I don't also think of a foot as a single entity or unit on its own. In that respect, I think of it as a bit more than a single hand span. What I meant is that, when dividing it, I don't just think of it as twelve divisions of an inch but also as two lots of 6 inches, 3 lots of 4 inches or 4 lots of 3 inches. The advantage of being divisible by 2, 3 and 4 is that the number of those smaller divisions can be comprehended instantly without having to count them. Ten is only divisible by 2 or 5. Two divisions is fine but 5 is not quite intuitive enough for instant recognition. 10 is way too many.

In a way, you've accepted that yourself by saying that you prefer a ruler with emphasis on the 5mm marks. When you are measuring 7mm or 8mm, you probably start from the 5mm mark and count forward or start from 10 and count back. With the benefit of an emphasised 5 mm mark, you may be able to go directly to the 7 or 8 mm mark without counting, but most people can't. Without that emphasis, no-one can do it consistently. Anyone who says they can is lying - they are actually counting back from the ten mark. Sure it doesn't take long but they are counting nevertheless.

Originally Posted by Grunt

This is a little spurious. You are quite right if I make something a meter high and want to put dividers two dividers at equal distance I'd use 333mm and at 666mm and I'll be out by .3 of a mm. I could have made it 900mm high instead and not had an issue. And there is no mark on the ruler for those. However, if I was 32", I firstly have to workout what a third of that is.

Yes I agree you can work around it with metric and I would do the same. That is equally true of imperial and in the example you gave, I'd opt for 30" or 33" and avoid the problem too. There is another solution though. I can't find it now but I had an imperial ruler of which a small portion was marked in 1/6ths of an inch with emphasis on the 1/2" mark. I think there was also a small section in 1/12ths with emphasis on the 1/4" and 1/2" marks. I think it was a wooden, folding ruler made by Rabone. Now there's a thought, customised rulers for oldies and the vision-challenged.

regards
Coldamus

I find the best metric tape measure to be a Stanley 8M that is all metric. Serial no. is 30-459.

Originally Posted by

I find the best metric tape measure to be a Stanley 8M that is all metric. Serial no. is 30-459.

Onya, ! A bit of practical advice amongst all the theorising.