# Silly question - why 4mm grid paper?

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Greetings and Salutations

I have recently acquired a couple pads of A4 graph paper, but with

4mm grids. As is may seem a statement of the bleeding obvious, but 4mm is not an integer fraction of either 1 cm or 1 inch. (what can I say, I'm back in the States, I get my choice of "N to the foot" relationships.) I've kludged my way around the scale problem - my question is: why 4mm grids? Googled "4mm" and get a lot references to UK scale modeling. Aside from the use of 4mm:1foot (on the prototype) I'm not really any more the wiser. Does anyone have any idea why 4mm grid paper? Or is this one of those mysteries of life?

tschus pyotr

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It's right up there with the use of paper that matches nobody else's paper. They have no idea what A4 means, but use Letter instead, and love Legal writing pads for jotting notes on. I still have a selection of US graph papers, I'll dig them out tomorrow and see what size grids they are.

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Davey on Fri, 12 Aug 2016 00:43:09 +0100 typed in uk.rec.models.engineering the following:

It all depends, some are four to the inch, some are five, both of which divide an inch into "usable" fractions.

But 4mm? - that's 2.5 grids per centimeter!?

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The metric system is virtually unknown in the USA, remember. I haven't got to my grid sheets yet.

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Simple, it's 5/32" which, coincidentally is the diameter of Meccano shafts ;-)

Regards Mark Rand

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And also the diameter of Maxon industrial burner joint securing Allen screws. Again, don't look for any relationship to metric measurements, such as

4mm, in US stuff.
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Mark Rand on Sat, 13 Aug 2016 01:34:13 +0100 typed in uk.rec.models.engineering the following:

Ah - things one doesn't learn, not growing up in the UK. :-)

tschus pyotr

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Davey on Sat, 13 Aug 2016 02:14:10 +0100 typed in uk.rec.models.engineering the following:

I'm not looking for a relationship to imperial units, I'm looking for a metric explanation why one would have a 4mm grid on the page.

tschus pyotr

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Maybe it's been determined that that is more useful than other sizes.

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Davey on Sat, 13 Aug 2016 11:15:51 +0100 typed in uk.rec.models.engineering the following:

Ah, the old "It made sense at the time" and "We don't know, it's just policy." explanation. Which makes sense, sort of, to someone.

Like I said "a silly question" and right up there with "Why do hot dogs come eight to a package, but the buns come six to a package?" and other conundrums.

tschus pyotr

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In this case, it may be that empirical testing has shown that 4mm-5/32" grid spacing is the most user-friendly of the available options. It might be worth your testing some close-but-different values to see if they work as well. Or not. It depends on how interested you are in solving your initial question.

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Probably not universally - 4mm is extremely unusual. 1mm, 2mm, 5mm and

10mm are, as you might expect, more common. 5mm and 10mm are especially common in Yurp, used as school exercise paper in France and elsewhere. People who used it to learn to write with it - one letter per square - often continue to use it instead of lined paper.

For some 5mm is too small, and 7mm, 7.5mm and especially 8mm squared exercise paper is also available.

But 4mm is uncommon - perhaps if we knew where you bought it from their customers might have a particular use for it?

-- Peter Fairbrother

>
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That should be asked of pyotr, not me.

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Up until he retired in 1980, my dad worked for a large paper manufacturer and as a kid I can remember him bringing home "graph paper" with odd sized grids. If my memory is correct they supplied it to professional model makers. This being before 3D CAD they were employed by architects / developers to produce quick mock ups of planned developments before making the final 3D model. 1 to 76 scale is 4mm to the foot which is still popular in the UK as it it is model railway 00 scale so that cheap models of road and rail vehicles were readily available to populate the models of large post war developments.

Nowadays you can print your own graph paper with any sized grids and companies like

can supply the files to print them from.

Alan

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Davey on Sat, 13 Aug 2016 21:30:28 +0100 typed in uk.rec.models.engineering the following:

I think I need to rephrase my question:

In a decimal world, which I assume that SI is (he writes lounge in cheek), a 4mm grid doesn't "fit". A 5mm grid works well, as two grids equal 1 cm, and you can scale 2:10 for what ever results you want . Two squares are a meter, a kilometer, an picometer, etc, and your metric ruler will tell you that as your line is 5 cm long, so your design is 2.5 meters/kilometers/picometers/whatsamatters. (You could do the same with cubits, fathoms, furlongs, spans, or Smoots (q.vid) but your ruler will still need to be metric: 5mm=1/2(unit), but I digress.) However with a 4mm grid, two squares do not equal a centimeter, which means that 1 cm on my ruler is now 2.5 grid squares so I've lost the 2 squares per unit relationship I have with a 5mm grid. I suppose that I could use some other scale where 1 cm on paper is

2.5 meta-units in real life, but I can't see how that works out as easier or simpler. Which leaves me back to my original questions intent: what were they smoking when they came up with this idea?
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Peter Fairbrother on Sat, 13 Aug 2016 23:01:53

+0100 typed >> >>

I got it from my wife's stash, and she got if from a second hand store. Hmm, maybe if I looked up the name on the cover... "Migros is Switzerland's largest retail company, its largest supermarket chain and largest employer." Well, that's interesting. "Zellstoff elementar chlorfrei gebleicht" translates to "Pulp elemental chlorine-free bleached" - wunderbar! Ack, the price has gone up, was 2.5 now 3.10. Such is life.

I think, as I look about, this seems to be a size not for graphs, but for writing in a grid. I had several such notebooks in Germany, could write either way as the book filled up, or space required.

tschus pyotr

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Where the heck is "SI" and how do you get your lounge in your cheek ?

Andrew

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Back in the days before computers, software and printers/plotters took over the world, results of tests and experiments were plotted by hand onto graph paper. There it did not matter much what size the grids were; much more important was the relationship between major and minor (and sometimes intermediate) divisions and whether your results could conveniently fit the size of paper. Decimal subdivisions were OK but if you have ever tried plotting on grids where the subdivisions were by 4 then you too will have suffered!

Henry

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Ah, the "we have always done it this way." reason.

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"Andrew Mawson" on Mon, 15 Aug

2016 10:48:20 +0100 typed in uk.rec.models.engineering the following:

known at home.

Nonchalantly. (Stupid typos.)

tschus pyotr

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