Tag: inch

I was walking through the metric jungle

Today was a wonderfully sunny day, so I said to myself, “Hey, why not take a stroll through the metric garden.”  (Why do I ask myself such things? Don’t ask me.) The metric stroll should be easy enough, with its scientifically simple base ten measures.  The simple meter is wonderfully divided up into 100’s and 1000’s for convenient lengths of measurement.  It also quickly multiplies into…umm, kilometers.  No one uses hectometers? Oh wait, the French kind of do to derive their hectare.  It’s funny, that hectare isn’t listed in SI.

It’s arbitary

Sure, the imperial foot may have been based on someone’s actual foot length, but it is a useful length for some industries. Its not nearly as arbitary as the meter, which is defined as the distrance that light travels within a vacuum in 1/299792458th of a second. Why does SI use a bizarre fraction to define the core unit of measure for their decimal system?

Maybe base ten numbers aren’t all they are cracked up to be. What, never heard of metric foot? Or for that matter, metric ton, metric inch, or metric mile. Why do all of these units exist? For all the berating that the imperial system gets, the measures within it are based on real world needs. Since ancient times, units very similar to the modern imperial system have been common place. That said, it may be important to note that both SI metric system and imperial system have goofy offshoots.

Missing units!

Hey, what happened to the liter? An entire unit of measure for volume is missing from the international standard! Did aliens abduct the liter for use on their alien world? Well, no. It’s actually very common in the US, if that doesn’t seem ironic. Oh, and don’t get diehards started on a discussion about the correct spelling of meter or liter!

Psst, USA is metric!

Something else that is ironic, the USA has been legally metric since 1866.  So, it’s not true that the USA isn’t metric.  Neither is it true that the rest of the world is 100% metric.  Specific industries, companies, populations and individuals still have the right to choose their standards and measures, both in the USA and elsewhere.  Pipe threads in France are NPT, not the ISO sizes that were meant to replace them.  Pints of bitter are still actual pints in Britain.  Speaking of Britain, I’m reminded of the TV show Top Gear.  Miles, horsepower and inches are so commonly used on that show, I forget that the UK is supposedly metric.

This stroll through the metric garden is starting to look more like a forced hike through the metric jungle.

Inch or Metric?

A recent discussion on eng-tips.com has prompted some interesting replies.  The discussion revolves around one individual asking for advice to help in the battle to promote metric at his company, despite push-back from their machine shop, and a lack of concern about the issue from higher-ups who have taken a pragmatic cost related approach. I believe that the responses received may have surprized this individual.

There are some who point out that the cost of switching to metric must be justified and explained to management.  The problem here is that there IS a cost associated with switching from a shop based on inch tooling to a shop based on metric tooling.  Is there savings associated with the switch?  The benefits of switching units of measure are likely limited, unless they are dealing with much more complex issues.  Once a company has a system in place, it is generally not economical to switch it midstream.

Several made the point that if the company is already standardized to inch, then any individuals at that company should adjust their methods accordingly.  This is the same if a person accustomed to inch joins a company that has standardized to metric.

What I personally questioned was the rather strange idea that metric is somehow some sort of default when it comes to making the choice.   The universe doesn’t know the difference between an inch and a millimeter.  For us in the engineering field, it is easier to think in metric than in inch, but what are the real world advantages of one system or another?  Unit of measure is completely arbitrary.  One person who responded to the posting even pointed out the advantages of using hardware from both systems at the same time.

“But the rest of the world is using metric!”  Umm, really? That, by itself, is an arbitrary point.

A counter arbitrary point, the United States of America has the largest economy on the planet by almost 2-fold.  It doesn’t really matter what rest of world does because the U.S. is so big. It’s like saying that the 800lb gorilla in the room should wear jeans just because all the chimps in the room are wearing them.  Maybe the gorilla is happy with his corduroys instead.

To this, there was a response about how the world combined outweighed the U.S. economy, and that the US is not 100% inch.  My point at that time was simple, “…Americans might be surprized by the number of countries that ARE NOT 100% metric, many of which are in Europe. ”

I was surprized by the responses that comment provoked.  There is apparently much less standardization going on around that planet that we’ve been lead to believe by hardcore metric proponents here in the U.S.  I know about the imperial gallon, the pint, and oddities like the metric ton.  However, I didn’t expect responses from the international community stating that there are significant fields and regions where standardization is in the old traditional imperial system and not metric.

The more I explore this topic, the more I’m convinced that it really just doesn’t matter.  Once a choice for a company is made, then they should stick to it.  I’m also learning that some strong proponents of metric here in the U.S. have a tendency to assume metric has greater adoption than what is true in reality.