Why mm?

[has.been]

Bring back the Chain, League, Cable & Rod !
Also, give me a Firkin rather than a Pint, any day! 

[Sir Barnaby Hammond-Rye]

Maybe they started corresponding to traditional - European - Toy Soldiers?

Zinnfiguren, Flats, etc which would have been all metric.

[Dolnikan]

One very simple reason I think is that it accommodates many more possible scales. After all, half inch, five sixth inch and the like don't run easily whereas mm scales are much more flexible and easy. It's the same reason why mini scales are in mm and not in cm.

I wasn't around back then, but if at some point the only scale was 25 mm, no one would have needed a name for it. But for multiple scales, especially ones that are important to distinguish (like 28mm) it's much more helpful.

[vodkafan]

While we are at it - why originally 25mm?  It's just such a small fraction over an inch,

 Small correction! 25mm is just UNDER an inch. 1"=25.4mm

[vodkafan]

and don't even think about what 10/12mm actually represents!

12mm is easy. it is 1/144 scale,
Exactly half the scale of 1/72.
I don't know about 10mm. I don't know why folks have started lumping 10mm and 12mm together as one, the disparity is huge to my eye. 

[vodkafan]

or to the model aircraft scale is the more easily understood 1 inch to 1 foot = 1/72. 

1 inch to 1 foot is actually 1/12 scale 

[has.been]

You tell them James

[dadlamassu]

1 inch to 1 foot is actually 1/12 scale 

My bad - I meant 1 inch to 6 feet!

[FifteensAway]

I believe 10 mm derived from 9 mm which was meant to match N scale (1/160) - I believe started by Jack Scruby as a wargaming scale - who inspired Donald Featherstone, by the way.

While there are all sorts of arguments as to where the "modern" hobby got its start, I land squarely with Jack Scruby.  And I think very likely the whole "mm" thing started with him. 

Don Featherstone got started after he split away from Jack Scruby's early newsletter.  The so called "Old Guard" of the hobby were the original subscribers to Mr. Scruby's newsletter - which included a number of names well known now.  I believe it was all of 40 people scattered about the planet.

Yes, there were earlier miniature wargamers all the way back to circa 1885 and Robert Louis Stephenson  (sp?).  [I discount the toys made for royal brats, that hardly constituted a hobby, just privilege]  But what we recognize as the wargaming side of the hobby today got its start and push from Scruby.  Before him you had to be able to afford things like Britains which were not cheap back in the day.

I had a school mate back in the early seventies who was building a Napoleonic army by using RTV rubber molds to make castings of what I am certain were Scruby figures - and since we were from the "poor part of town" there was no way to buy all the figures so he cast his.  Don't condone, just what he was doing.  Another school mate created - from scratch - beautiful sailing ships in wood for naval games, something we actually played a few times, my first 'real' miniatures gaming, knocking on 50 years ago!

Now we have 2 mm, 3 mm, 9 mm, 10 mm, 12 mm, 15 mm, 18 mm, 20 mm, 22 mm, 25 mm, 28 mm, 30 mm, 32 mm, 40 mm, 42 mm, and 54 mm.  (well larger sizes of figures but never heard of much gaming with them - if any).  And then there are all the naval and airplane sizes of miniatures that I don't really follow.  And you can game from the dinosaur era past and far into the future with a wee bit of actual 'history' figures in between.  And I thought model railroading was diverse! 

[2010sunburst]

Wouldn’t disagree with almost any of that Fifteens, but 9mm is the track gauge of standard gauge outline N scale trains, not the height of the figures.  It’s the scaled equivalent of four foot eight and one half  inches….if it was the figures they’d be a little short 

[Etranger]

I believe 10 mm derived from 9 mm which was meant to match N scale (1/160) - I believe started by Jack Scruby as a wargaming scale - who inspired Donald Featherstone, by the way.

...... And I thought model railroading was diverse!

N scale isn't a scale, it's a gauge (9mm). The scale varies from 1//144 (Japanese) through 1/148 (UK), 1/150 (Japan), 1/152 (also UK) to 1/160. (Europe. USA).

[2010sunburst]

…..and that’s before you start investigating the narrow gauge aspects of railways, such as OON3, or OO9 …..they are in a worse state than us 

[FifteensAway]

Check out this link, scroll down to the second topic: http://littlemenatwar.com/the-little-men/

Never saw the comment about Jack Scruby's 9 mm (also referred to in another link as N-gauge: http://historifigs.com/site/war-game-miniatures-retired-subjectsthemes/) being something akin to 15 mm - though I think the author misspeaks.  I have seen and gamed with some of those 9 mm/N-gauge figures and they were not 15 mm unless maybe you count some of the very smallest 15 mm figures, like Pat Condray's old ranges (Mike's Models squat little models were 'monsters' next to Condray's figures - at least the ones I had); those Condray's were dwarfs next to most 15 mm figures.  I have a collection of Pendraken Vietnam figures and they are close to the old Scruby 9 mm.  And those 9 mm figures were a good deal smaller than the Minifigs 12 mm figures, ordered some to supplement my Vietnam Pendraken figures.  Historifigs still markets some of the Scruby figures - or did though I don't think the smaller figures anymore.

With all the realties of N-scale/gauge/9 mm track, Scruby listed his smallest figures as N-scale and 9 mm.  Of course, we are talking back into the later 1960s or very early 1970s when these figures were released. 

[vodkafan]

 Fifteens Away, good digging. Certainly enough evidence there to make it very probable to me that 10mm WAS deliberately based around the N gauge.  Even if 9mm did represent the width of track at 4 foot 8.5 inch, (as I believe someone mentioned), then 10mm would be the right ball park for an average man's height using the same scale. We can further safely assume the 1/160 scale ratio, as Scruby was in the US and the US version of N gauge is 1/160.

[FifteensAway]

http://www-personal.umich.edu/~beattie/timeline/wgdsublistsm.jpeg

The "Old Guard" from Wargames Digest, started 1957.  Notably absent?  Donald Featherstone.  Be curios to know when he first signed up for the newsletter.

There are other names many will know like Larry Brom and Charles Grant.