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.