by Steven D. Johnson
Full Immersion Learning - A Woodworker's "Metrification"
An Inspiring Woodworker – "Us Little Old Ladies..."
My Local Woodworking Store...Killing Our Hobby One Customer At A Time
And, A Little Fun At My Neighbor's Expense
Full Immersion Learning
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A quarter-century ago my employer sent me on a two-year assignment to live and work in Italy. My destination was a small town in the Northeastern part of the country, an hour to the beaches of the Adriatic and less to the foothills of the Alps. I spent the plane ride studying my English-Italian phrase book, trying desperately to memorize what I then deemed imperative; "Dov'è il bagno?," "Dove posso trovare un po 'di cibo americano?," and importantly "Parla inglese?" The time spent was wasted.
My new co-workers smirked at my Texas-tinged American version of English, and outright laughed at my mangled attempts to speak the phrases I had tried so hard to memorize. And even though they all spoke English, they refused to help, instead admonishing, "Vuoi vivere qui, è necessario imparare a parlare la lingua" (you want to live here, you better learn to speak our language!).
And so I became immersed… not by choice, but by necessity. My new friends made sure, by speaking privately with waiters, shop keepers, and others, that if I did not speak to them in Italian I was to be left on my own, perhaps to go hungry, perhaps to be unable to find a restroom, buy toothpaste, or (oh my gosh!) get a date. I learned quickly.
It was this immersion in day-to-day conversation that taught me not to try to think, translate, or memorize that the word "bread" in Italian is "pane," but rather to smell the fresh-baked bread enticing me to the corner bakery and think "Delizioso pane appena sfornato" (delicious bread just taken from the oven). In other words (tortured play on words), my mind wasn't doing the mental gymnastics of hearing "pane," translating that to "bread" and then thinking of bread… instead, when I heard "pane," my mouth started watering and my stomach made hungry sounds. I had bypassed the translation step and become immersed.
As it turns out, Immersion Learning is a recognized and well-established methodology, particularly for language learning, thanks to our friends and neighbors to the north. Canada instituted what are generally regarded as the first formal immersive language learning systems in the 1960's and have been leaders ever since.
Learning to use the metric system of measurement in my shop was, at first, a bit like trying to memorize phrases from a guidebook… useless. After a tortuous and frustrating few weeks of trying to memorize conversion factors, my long-ago immersive learning experience reminded me of the folly I was indulging. I needed to immerse myself and begin to see a piece of wood, not as 3/4-inch thick, which equals about 19 millimeters, but to see that piece of wood as simply 19 millimeters… period.
Before I describe and demonstrate the absolute superiority of the metric system, its sublime simplicity, its accuracy, its convenience, and its efficiency, it might be appropriate to review just exactly how we wound up with our arcane system of inches, feet, and yards and our fractional sixteenths, eighths, and quarters. Mostly we can blame the rapid growth of America and one of the vagaries of capitalism – namely, that entrenched systems are hard (and expensive) to displace.
By the time the colonies began the struggle for independence from England, the British system of weights and measures was in widespread use throughout our fledgling country. Changing it would simply have been too much trouble… too disruptive and too costly… and it wasn't a high priority. Instead, we kept the system of feet, yards, chains, furlongs, and miles. Of course, being the independent revolutionaries we were, we also, over time, made our own modifications and stubbornly refused to modify the things that England eventually changed, refined, or better defined. Thus we have the system we have today, with all its complexity and illogicality. And while Great Britain has formally adopted the metric system of measurement, their changeover is far from complete. Our irrational differences continue, like the British Imperial pint that contains 20 ounces, compared to our American pint with 16. At least in this instance chalk up one significant advantage for British pub-goers.
The inch, the woodworker's fundamental measurement, was established in England some 900 years ago, and was defined as the length of three barleycorns arranged end-to-end. Sounds accurate, huh? Along the way, some intrepid stickler for detail honed the definition a bit more, stipulating that the barleycorns should be "well dried… and from the middle of the ear," thus roughly the same size. Some accounts attribute the inch measurement to the width of a man's thumb. Thumbs were perhaps more similar in size than barleycorns in those days.
Along the historical line, someone needed a measurement smaller than the inch. The barleycorn was again used. Think how simple our rulers would be today, with the inch only divided into thirds! It might be fine enough for a framing carpenter ("Say Joe, cut me a stud 95 inches and one barleycorn long!"). Furniture builders need a finer measure, so some divided the inch into fourths, some into tenths, and some into twelfths (called "lines"). Accounts of history vary, but as you well know, the system of fourths, later "subdivided" into eighths, sixteenths, thirty-seconds, and so on, prevailed. Thus we have today our arcane and cumbersome, but thoroughly entrenched system.
In order to immerse myself fully… to achieve full metrification… it was important to make the change in every aspect of my life. My wife often complains that I drive too slowly, and soon after my metric immersion when she coaxed me to speed up, my response was, "I'm doing 100!" Of course, in kilometers per hour, I was still moving more slowly than the other traffic.
Conventional wisdom and the Specialty Coffee Association of America call for 0.36 ounces of ground coffee per cup of water for the perfect brew. What the heck is that? My digital scale gives fractional ounce readings in 1/4, 1/2, or 3/4… not in decimal fractions.
Until now getting the just-right brew for various coffees has always involved a bit of guesswork and a total lack of repeatability. After consulting the instruction manual, I was able to convert the digital scale to metric weights, and now I can fine-tune my brew to the gram. Nominally 10 grams, I can adjust to 9 grams to compensate for a bean roasted darker, or to 11 or 12 grams to compensate for a milder roast. I can "dial in" the perfect cup of coffee now and do it in a reliably replicable way.
I obsess over my weight in kilos now ("That restaurant was so good, but I think I gained a kilo!") and I measure my walks in kilometers (It's just 3 kilometers to the grocer, I think I'll walk."). I am as immersed as current systems allow, though I still have to think "gallons" at the petrol station and measure in cups and quarter-cups to follow most recipes in the kitchen.
In the shop, the metric conversion immersion has been easy. For one thing, I probably measure less than a lot of people. Between story-sticks and cut-to-fit, I just don't measure a lot. When I do, I use just a tape measure and a small pocket rule. Replacing the pocket rule with a metric version was easy. The tape measure, though, was not. I am a little fussy when it comes to tape measures. There are probably at least a dozen orphaned tape measures in drawers, boxes, and bags hidden away in my shop, but only one that I really like and use. Finding a metric tape measure proved to be just as difficult. After several aborted attempts, I finally found one that felt "just right." If you are interested, it is the FastCap ProCarpenter 5-Meter Flat Back Metric. You may already have a tape measure that features dual imperial and metric measurements, but I discourage you from using that. Having the inch-equivalents on one side of the tape will not allow you to fully immerse yourself in the metric system. You will keep trying to translate. It would be like having a Star Trek language translator in my pocket in Italy… I never would have really learned the language.
Figure 1 - The FastCap tape measure feels comfortable,
works well, and lays flat against surfaces
Full metric immersion in the shop requires commitment and diligence. Our current system is so ingrained, it takes an act of strong will to abolish the inches, sixteenths, and eighths from our vocabulary and thought processes. But the effort is well worth it.
Let's take a common task as an example. Assume you have a 25-3/8" wide drawer front in which you would like to install two knobs exactly equidistant from the edges and double that distance between the knobs (Phi devotees, please don't email me… I'm just making a math point here!). Something like this:
To divide 25-3/8 by 4, you must first either convert the fraction to its decimal equivalent (25.375) and convert back to fractions after the calculation is done, or divide the nearest whole number divisible by 4 (in this case, 24) and then divide the balance (1-3/8) by 4. The balance of 1-3/8" will need to be converted to its fractional equivalent (11/8) and then you can divide the numerator by 4. Either way, you are not going to get an even number.
Since there is no mark on your ruler for 2.75-eighths, you will wind up estimating or fudging or compromising. In the meantime, I'll bet you have given yourself a headache!
In the metric system, your tape measure would tell you that the drawer front measures 644 millimeters. This calculation is infinitely easier…
644 ÷ 4 = 161
Now measure in from each edge of the drawer front exactly 161mm, make your mark, and the knobs will be right where you want them.
Consider this real life task from my shop… A couple of weeks ago I needed to cut four blanks for stretchers between aprons for a desk project. The space between the aprons was 22 1/2". The front apron was 7/8" thick. The rear apron was 3/4" thick. I wanted the stretchers to have through tenons with a 3/16" reveal in the front, and buried tenons in back, half the depth of the rear apron. How long should I cut the blanks? The math looked like this:
3/16+7/8+22 1/2+(3/4÷2)= ???
Adding those numbers required that I first convert everything to a common denominator. So the new math looked like this:
3/16+14/16+22 8/16+(12/16÷2) = ???
Next I got rid of the "buried calculation" in parenthesis:
3/16+14/16+22 8/16+6/16= ???
Only then could I add up all these sixteenths and arrive at 22-31/16". Then I could convert the 31/16 to a more proper 1-15/16, add that to the 22" and get my final measurement of 23-15/16. Whew!
In my new metric state-of-mind, I simply added my desired reveal (5mm) to my front apron thickness (22mm), added in my distance between aprons (571.5mm), halved my rear apron thickness (19mm ÷ 2 = 9.5mm) and added it all up:
5 + 22 + 571.5 + 9.5 = 608mm
No headache. No thinking. Very quick and easy.
The learning that only develops with time, of course, is the mental image. Exactly what does 608mm look like? When we hear 50 X 100mm we do not yet automatically conjure a vision of exactly what that looks like, but when we hear 2 X 4, we do. Well, they are the same. Actually, 38mm X 90mm are the actual measurements, just as 1 1/2" by 3 1/2" is the actual measurement of a 2" X 4."
If all this sounds confusing, it really isn't. It is a matter of getting used to envisioning things in a different language. Just like "pane" conjures a vision of bread, 300 millimeters will soon conjure a vision of something about as long as your foot...I promise.
The metric system is easy to use, it is infinitely logical, it is predicated on a base-ten calculation, which makes its division and multiplication very easy, and it is way more precise. Our hobby and our industry need to make this change, but when it will happen is open to much speculation. Even the American Wood Council has stated, "Little incentive exists for the wood industry or wood products users to change to metric in the US." Someday, though, a new generation of carpenters and woodworkers will gradually force the change. Until then, do yourself a favor and try building a project while fully immersing yourself in the ease of the metric system. It will be an eye-opener for you and who knows? You may not want to go back to fractions and inches.
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