Measurement Systems and Bridging Between MMGS and IPS Systems

The MMGS (millimeters, grams, seconds) or metric system became universal and was accepted all around the globe. No doubt, it is simple, handy, decimal by nature and use decimal fractions. Millimeters are small units, easy to visualize and reflect acceptable for model making tolerance. I personally love millimeters as main measurement units and train my crew to think in millimeters as well.

Truth is, however, that the main measurement system in the United States is traditional IPS (inch, pound, second). We can argue endlessly about convenience of this system, advantages, disadvantages and reasons why Americans are holding onto this system. This argument is not relevant and article is not about it. IPS system in the United States does exist, it’s alive, used every day and will be in active use for a while. It is a fact that has to be accepted.

Professional model maker working in USA or with US specialists must comprehend in both measurement systems and operate freely with metric and non-metric units. Bridging between MMGS and IPS is surprisingly simple. There is no a slightest reason to feel confused or frustrated, there are only a few numbers to remember.

1″ (1 inch) = 25.4mm (25.4 millimeters)

1mm (one millimeter ) = 0.040″ (forty thousands of an inch)

And that’s simply ALL you have to know! Remember these values and you will be comfortable with both systems from now on.

Model Scale, Part 4 – Selection of Scale for Architectural Model

In some cases architects request a specific scale in which they want the model to be built. In many cases architects are setting a target size for the future model and ask  model maker to come up with suitable scale.

The main objective is to select a scale that will match or will be very close to one of  standard scales in modeling industry. Why? Because of scenery elements that are pre-manufactured and available to buy off shelf and to add to the model. Use of scenery produced by railroad models manufacturer is preferred – this industry provides a greatest assortment of such elements, which are usually of high quality, available and affordable.

Scenery elements include first of all people figurines, cars and vegetation. Adding scenery to the model is not only a way to make it fancier and life-like looking. It provides instant comparison reference for understanding a size of the subject.

Below is a table showing some of the most usable architectural model scales along with transcription to standard US inch/foot scales and recommended scales for accessories/scenery elements.

Below is a chart that may assist in selecting an appropriate scale range for the future architectural model, based on model content and purpose.  After selecting an appropriate scale you might refer to the chart published in article “Model Scale, Part 3 -Architectural Scales” to see which standard scales are appropriate for use of scenery elements. Of course, described here only the most common types of models, as I would not be able to cover all possible combinations in one chart .

Model’s Content	General Purpose	Recommended scales
Single, up to 1-2 story, small to medium size building, no landscape development	Museum, exhibit	1:24, 1:32 , 1:50
Single, up to 1-2 story, small to medium size building, limited landscape development	Museum, exhibit, architectural presentation	1:32, 1:50 , 1:48
Single, up to 5-7 story, medium size building, limited landscape development	Museum, exhibit, architectural presentation	1:75, 1:100
Single, multi story building, tower/skyscraper type, limited landscape development	Museum, exhibit, architectural presentation	1:100, 1:120, 1: 150,   1:160, 1:200
Single, school/hospital type building, expanded landscape development	Architectural presentation	1:150, 1:160, 1:200, 1:220,   1:240
Multi building complex consists of small to medium size buildings, expanded landscape development (residential block type)	Architectural presentation	1:220, 1:240
Multi building complex consists of medium to large size buildings, expanded landscape development (commercial, industrial type)	Museum, exhibit, visitor center, architectural presentation	1:300
Medium size resort complex, expanded landscape development	Visitor center, architectural presentation	1:240, 1:300
Large size resort complex, greatly expanded landscape development	Visitor center, architectural presentation	1:480, 1:500
Urban model, several building blocks, doors, windows and other details still be required, expanded landscape development	Urban development support	1:480, 1:500
Urban model greater than a preview one, buildings are fabricated as blocks, no doors, windows required, mono or duotone painting scheme	Urban development support	1:1000, 1:1200, 1:2000, 1:2400 depending on area’s size

Model Scale, Part 3 – Architectural Scales

Common architectural scales are in most cases different from standard scales developed by modeling industry, although some of them are come very close.

In United States architects used to scale represented by inch/foot relations and sometimes have little knowledge of unit-less “international scale”. It is not a place and goal of professional model maker to educate architects. We have to speak with architects their language, equally comprehending in both systems.

Below is a table showing some of the most usable architectural model scales along with transcription to standard US inch/foot scales and recommended scales for accessories/scenery elements.

International Scale	1” of the model based equivalent	1′ of the origin based equivalent	Other equivalent	Recommended standard scales for scenery elements
Architectural Models
1:10	1” = 10”			1:9
1:16		3/4″ = 1′		1:16
1:20	1” = 20”			1:22.5
1:25	1” = 25”			1:24
1:24 *	1”= 2′	1/2”=1′		1:24 , 1:22.5
1:32	1”= 2.66′	3/8”=1′		1:32 , 1:35
1:48	1”= 4′	1/4”=1′		1:48 , 1:50
1:50 *	1”=4.16′			1:50 , 1:48
1:75	1”=6.25′	3/16”=1′		1:72, 1:76
1:100*	1”=8.33′	1/8”=1′		1:100, 1:87(HO)
1:125	1”=10′	3/32”=1′		1:122(TT), 1:100
1:150	1”=12.5′			1:160(N)
1:160*	1”=13.33′		3/4”=10′	1:160(N)
1:200*	1”=16.66′	1/16”=1′		1:220(Z)
1:240*	1”=20′			1:220(Z)
1:250	1”=20.83′			1:220(Z)???
Urban Models
1:300	1”=25′			1:287
1:360	1”=30′			n/a
1:384		1/32”=1′		n/a
1:480*	1”=40′			1:500
1:500*	1”=41.66′			1:500
1:600	1”=50′			1:500???
1:1000	1”=83.3′			n/a
1:1200*	1”=100′			n/a
1:2000*	1”=166.6′			n/a
1:2400*	1”=200′			n/a

Table legend: * most recognizable scales; ??? be careful, scale deviation is significant

Model Scale, Part 2 – Standard Scales

1:43 scale model of M5 Artillery Tractor

Although history of modeling industry is relatively short, we cannot possibly track a development of all standard scales and find an explanation for each particular scale. Because railroad models were the earliest products for modeling enthusiasts, there is no doubt that most of standard scales derived from these set for railroad models. The most popular scale in 1930-s England was O (or O gauge) which is 1:43, known today more as a standard scale for die-cast car replicas. Later, due to miniaturization of railroad models, US manufacturers developed a new scale by dividing the O-gauge in half – 1:87 scale or Legendary HO (see the connection in a letter code: half-O). HO scale today became the king of railroad scales that conquered the whole world. Approximately at the same time in UK another standard railroad scale was developed – OO gauge, the 1:76. OO trains were slightly larger than HO ones, however they were also compatible to the 16.5mm railroad track.  For peculiar model maker a deviation between 1:87 and 1:76 scale is huge – 11 units. However for about two decades manufacturers tried to promote both scales as compatible, even were labeling their products as HO/OO. A birth of 1:72 scale is even more interesting. This scale, where 1 inch represents 6 foot was originated in UK in 1930, developed by companies producing aircraft replicas mostly for military recognition training. Some UK manufacturers starting 1960-s were producing plastic kits in 1:76 scale but labeling it as 1:72 scale. Later manufacturers switched to the true 1:72 scale. I the beginning of 1960-s Tamiya (Japan) came up with motorized plastic tank kits. 1:72 scale product would be too small to accommodate the electric motor, so Tamiya came up with 1:35 scale, which is awfully close to doubled 1:72. 1:35 scale became a hit and remain the most popular scale for military plastic kits till present.  Throughout the history of standard scale’s development you can discover a connection between most of them when you will start dividing in half or doubling. Don’t forget, however, that the larger the sale, the lower the numeric value of it, and another way around.

Architectural model in 1:160 scale. Note a massive use of N gauge cars and vegetation.

It is nice when professional model maker has knowledge of scale predominates in terms of general education, but not a necessity. However, a model maker has to know by heart current standard scales and types of prefabricated models and accessories available. When it comes to architectural models, matching the scale of future architectural model to one of the standard ones is a must in order to use prefabricated scenery elements.

It is also important when model maker is commissioned to develop a scale model or replica for mass production, as each  standard scale product has its own tradition and must-to-follow requirements.

Below is a table of some of the most popular standard scale for a number of industry’s fields and directions.

Industry	Associated Standard Scales
Railroad models(including lettering codes)	1:220 (Z), 1:120(TT), 1:160 (N), 1:87 (HO), 1:76 (OO), 1:43 (O), 1:24 (G)
Car Models	1:64, 1:50 , 1:43 , 1:24 , 1:18
Aircraft Models	1:500, 1:144, 1:100, 1:72, 1:48, 1:32
Military Miniatures, AFV	1:287, 1:72, 1:76, 1:48 , 1:35 , 1:18
Maritime Models	1:1200, 1:1000, 1:700, 1:300, 1:200, 1:100
Dollhouses	1:50, 1:32 , 1:24
Figurines	1:50, 1:35, 1:32, 1:24, 1:22.5, 1:18, 1:14, 1:9, 1:6