Metric Rules or Does it Really?

I worked through school when there were 20 shillings in pound, 12 pennies in a shilling and thereby 240 pennies made a pound. Within that structure we also had farthings, 4 to a penny. half pennies, threepenny bits, sixpenny bits, half crowns and so on. Was it complicated? Not really. I found it quite simple. Eventually we went to the metric and that ended confusion for foreign visitors from other continents and united us with Europe.
Another obstacle to mainland Europe was the non metric imperial system of measuring. Dead simple system of dividing an inch by any number you want and then subdividing those by halves and quarters hence half inches, quarter inches, eighths, sixteenths, thirty-seconds, sixty fourths and so on. To some, it didn’t make any cents. Oops! I mean sense.
DSC_0156On eBay last week was a three foot fourfold rule made by Rabone Chesterman when Made in England meant something. This ruler was divided up on one side in 16ths and on the other side in 10ths. The seller advertised it as both an imperial and metric. Not deceptive but more a lack of knowledge of the facts I suppose. I paid £8 for my scarcity because no one wants imperial measurements, but the rule mirrored one I bought as a young aspiring joiner, replete with red seals still in tact and in place. DSC_0158I have several Rabone Rulers I’ve collected over the years and i use them at the bench for some work. When I was a boy men wore none fashion men’s workwear usually bought as bib and brace overalls that slipped over our general clothing such as jeans. In and along the right leg starting at from bend of the knee and down was a long ruler pocket that took the 9” length of the folded rule. No one I knew used a tape measure back then. My original rule is still current for me. When I was in school we were imperial, Metric invaded in the late 60’s and we converted to longer fourfolds that were ungainly and awkward. I migrated to the US in 1987 and was shocked to find feet and inches back in my life. I converted back to that. IN 1999 I returned to the UK to start New Legacy UK and switched back to metric to find half of the UK population did, like me, understand and indeed work in both unit types. Anyone under say 40 didn’t generally work outside of metric.


  1. John C on 3 April 2014 at 1:31 am

    I have lived in Illinois all my life. When I was in grade school, back in the mid 70’s there was this huge push for us to learn the metric system. We were told we would be left behind by the rest of the world if we didn’t adapt. I am not sure how long our education lasted in the metric system, it was about long enough to confuse the hell out of me, before the whole concept died out.
    I believe the US has got to be on of the very few countries left that holds out on the imperial system, and I am perfectly fine with that. I will admit that dealing in fractions of 10 seems very simple from the outside looking in, but I think the imperial system seems to be more precise, especially when dealing with tool and die maker and machine shop operations.
    Let the games begin

    • Alex on 23 March 2019 at 1:47 pm

      Just reading through Paul’s entire blog, so joining the games very late here but I just love this debate 🙂

      I’ve used both systems and metric is actually quite simple if you learn it as a child and it’s the first system you learn. I believe that is both because dividing and multiplying by 10 is easy and also because you don’t have another system to ‘convert to and from’. Once you’ve learned and got used to one system, I believe _any_ other system will be ‘worse’, simply because it’s not what you’re used to. You will always compare it to the ‘easy system I already know’.

      Of course the system you already know will also be ‘more precise’, because the converted values will all be weird fractions but this goes both ways. Look at Paul’s workbench plans. Everything sized in inches makes perfect sense but if you convert that to metric it will be ‘off’ and ‘imprecise’ with fractions. If you just design the whole thing in metric, everything will make perfect sense and fit and measure easily but converted to imperial, it will be weird fractions. It’s all about standardization. Try to find a 7/32″ plane tote screw nowadays or a tap and die for that. Impossible, because everything is standardized to 1/4″ now but 100 years ago it was ubiquitous.

      Like Andy down in the comments, I know both systems now and can estimate lengths in both systems as well. It’s all down to accepting it and working with it instead of converting. I’ve lived in both Germany and Canada (and we use a weird mix here, where houses and furniture etc. are built in feet and inches while we drive 600 kilometers from Toronto to Montreal. Actually we measure distance in hours too for longer distances like that, because the speed limit it 100km/h, so we’d say that Toronto is 6 hours from Montreal. We measure our height in feet and inches while we weigh ourselves in kilograms. I still can’t tell you what a good summer temperature is in Fahrenheit though, because we use metric for that in both countries but I’m quite sure that if I went to live in the US I would get used to that as well). I do everything in feet and inches here, woodworking wise, while I’d do it in metric if back in Europe, as everything I source will be either in imperial or metric respectively.

  2. johnnie skears on 3 April 2014 at 2:40 am

    Since we’re of the same age I too went through all of the above,and what a waste. I’m sure that there are those that will support Napoleons long standing edict to rule the world,but I’ve never really got to grips with it. I work in a builders yard and the majority of customers young and old, still come in asking for 2×3 or 4×1, can’t think their all humouring the “old fella”.

  3. Tom Benim on 3 April 2014 at 2:45 am

    My thinking is that for a single craftsman, individual preference rules. But for global industry SI (metric) is preferred. A side note. I just retired from a company that is more than two centuries old and we still used some Roman abbreviations (M = 1000 and MM = 1000000) !!
    Not to mention a few units that were expressed as a combination of metric and imperial.

    • Paul Sellers on 3 April 2014 at 4:32 am

      Feet and inches make so much sense to me still. Talk to metric only people and say that and they look at you as though you grew two heads or you are accused of being stone aged yet I find people today rarely can visualise a distance between their hands or fingers accurately and express it when people could express feet and inches quite accurately. That’s just my observation working with people. Working in both systems daily because of living in a metric culture I find myself working in inches and indeed working with those raised in metric adopting imperial very readily. I think it very practical to work in both and so that’s what I do.

      • ray morrell on 3 April 2014 at 11:11 am

        even at the age of fifty seven ,i still have to convert in my head back into imperial so i can visualize the length.
        still change new pence into old d.
        and thats after forty years in heavy engineering.

  4. Paul Fowler,USA on 3 April 2014 at 5:22 am


    How well I rember. Working for government contractor (Lockheed), we were not allowed personal measuring tools. all were supplied by them. In the early sixties, management announced, due to adoption if SI (metric) blueprints will be metric exclusively! Rather than replace all measuring tools they issued calculators to employees! Still have mine.

  5. Reinoud Delporte on 3 April 2014 at 8:13 am

    Growing up in Belgium metric is the “natural” way for us. As a kid it just makes more sense when you can link meter to kilo and to liters. Very basic and straightforward system, no confusion. The same with the Celsius degrees, freezing is zero, boiling a 100 degrees. Straight forward.
    Over the years I did get in touch with a lot of imperial of course. Bicycle wheels, the sizing of my drumkit, vinyl records, lumber sizes, …
    Whenever I’m looking to plans made in imperial I always have to use a conversion app. I just can’t think in imperial. And when it comes to weight it’s a total disaster. The English system with stones and pounds… try to explain that to a kid 🙂
    I think the metric system is just handier and more precise.
    Back in 2002 when the Euro came along I was afraid I would have to convert to Belgian Francs for the rest of my life. Now I can’t remember when I did this for the last time.
    It’s all about habits to me.

  6. António Samagaio on 3 April 2014 at 10:14 am

    Around here, in Portugal, we use metric. But… all the plumbing stuff is in UK imperial, bow saw blades too, some kinds of bit, and the big axes, adzes, and agriculture tools are in pounds (the weight),go figures….
    I’m almost 40, and i learn from the 1st grade every thing (about measuring units) in metrical and decimal.
    But… when was a kid, i bought beans, flour, sugar in different measures, very similar to the imperial system -a bit of history- in XIX and early XX century we had the British and the French people around, plus our own kings systems.
    In the last 115 years we had 3 different coins (reis, escudos and euros).
    The result is… from north to south a very big mix of units

  7. Ed on 3 April 2014 at 11:52 am

    I use whatever the ruler at hand happens to be. It’s really as simple as that. The only pain is converting from one system to the other. Either do it or don’t- the choice is yours, but the need is unlikely to go away. The US, where I live, has been whining about this for so many decades that my inclination is to form a “We just don’t care any more” society. Sorry if this reply seems strident. I’m a scientist by training and units are just another set of tools. Use what is appropriate or what you prefer. Master them or limit what you can do. Measure work in horsepower fortnights? Sure, why not. That all being said, I visualize quantities in Imperial units, but that just reflects what I learned as a boy. Someone will say, it is easier to deal with metric decimals than Imperial fractions, e.g., when you must scale something. That is true, but it is even easier not to measure at all and just transfer a dimension from a pattern or from your work with a knife.

  8. elvishefer on 3 April 2014 at 2:48 pm

    My only gripe about having multiple units of measurement is how it can break down in a global market of products.

    For example, I bought a Japanese square a while back because I liked the size of it, and it’s come in handy many times since. On one side, inches. On the other side metric. Perfect, I thought, living in metric Canada as I do.

    But the manufacturing company’s logo had to go on it, and it’s on the metric side. What could have been a very handy 50 cm side is a 45 cm side with a picture. That picture doesn’t help me measure, so I inevitably have to turn it over and use Imperial.

    Reminds me of Paul’s ruler above… lip service paid instead of the best possible tool.

    I also encountered similar problems when browsing Lee Valley’s catalog for metric Forstner bits. There are gaps in the product line where I’m guessing I’m supposed to buy Imperial bits instead. But the sizes are never precisely the same as their metric counterparts. Very annoying.

  9. Sylvain on 3 April 2014 at 3:15 pm

    How funny that someone speaks about Napoleon as imposing the metric system.
    The decision to measure the terrestrial meridian was signed by Louis XIV in 1790; the work started in 1792 and the the length of the meter was established in 1795 long before Napoleon become First Consul (1799) and later Emperor (1804).
    In fact the French population was so against it that Napoleon made backtrack.
    This resulted in the fact that the first States where it became definitely mandatory was not France but Netherlands (including at that time Belgium and Luxembourg) in 1820.
    So this has been the legal system in my Country for nearly two hundred years.
    It became mandatory in France only in 1840.
    The international meter convention is from 1875, Napoleon was dead (1821).
    Speaking of Napoleon in this context is just propaganda.

    I recommend the following book:
    “The Measure of All things – The seven-year odyssey and hidden error that transformed the world” by Ken ALDER – The Free Press – 2002
    Also available in other languages.

    Viewed from Belgium, it seems that in US, everything is done to lure the Customer or at least to cut any obvious ink between the advertised quantity and the real thing. Use of numbers with no direct link to dimension, gauge system: when the number is higher, the dimension is smaller and so on. Strange units like boardfeet where contrary to what the word “feet” suggest, it is not a length but a volume. A 2X4 which is not a 2X4 but only 1 1⁄2 in × 3 1⁄2 in. and so on …
    (found on wiki : “For example, a #4 screw is 0.060 + 0.013 * 4 = 0.112 inches in diameter.”)
    Contrary to the rest of the world where 30 cm³ of water will wheight 30 gramme, one US fluid ounce of water will wheight 29.573 gramme, one Imperial fluid ounce of water will wheight 28.413 grammes while an ounce avoirdupois is a wheight of 28.349 grammes. The use of the term ounce is totally confusing.
    This total disrespect to the Consumer is unpalatable.

    The advantage of the International System is its coherence. When you do engineering, you don’t need strange factors to combine different quantities. This is a real bonus when you use various quantities : length, area, volume, time, speed, force, energy, power, temperature, current intensity, electrical tension, angle, …

    In woodworking you don’t combine quantities, you just need one quantity: length. So any length unit will fit
    You don’t even need to measure (except to go to the lumber yard); you can use a story board.
    PS Paul when you were explaining shellac, you used gallons without specifying US or Imperial gallon. Although it does not seem to be critical as the explanation with metric units could not be reconciled with any of those.

    • Paul Sellers on 3 April 2014 at 5:49 pm

      I suppose my moving to the US reintroduced me back to imperial and that being so I work with what I have know the longest. having worked with bot systems though, there may be more to the fact that I gravitate to feet and inches, miles and yards. I feel comfortable working with inches but when I teach classes here in the UK my students are conditioned to metric and that;s generally what I use.

  10. Salko Safic on 3 April 2014 at 4:50 pm

    I live in Australia and at school we were only taught in metric, when I started working with wood imperial became the dominant units of measurement due to plans mostly available to me were in imperial. So I had to get my head around it which wasn’t easy at first, still even after all these years I think in metric and struggle with imperial. To me metric makes more sense and is extremely easy to learn and use. I don’t understand why the US struggles with it.

  11. whitneyturk on 3 April 2014 at 5:35 pm

    Y’all. Jesus. Whatever system you learned first is one that seems intuitive. That intuition is arbitrary–obviously.

    Metric is great for a lot of things. It’s certainly a better way to do scientific measurement, particularly when you’re dealing with very small or very large measures that are orders of magnitude different from what we’re doing in a woodshop.

    Imperial has a great deal more utility for primitive life. When you’re measuring distances no smaller than 1/64 and not much larger than a few feet, imperial wins out because you can divide feet by 2, 3, or 4 (and therefore 6, 8, 9, and so on). In weight and volume measures, it’s multiples of 2 with similar utility.

  12. grego on 3 April 2014 at 7:06 pm

    In oil refining, a common way to describe how much material is being processed is “barrels per day”, sometimes even in countries that adopted the metric system. I have heard of one refinery in the UK that switched over to “cubic meters per day”, to the total confusion of plant operators. The clever training department constructed a wooden box that was 1 cubic meter in volume, and brought each of the operators over to look at it, one at a time. “Behold, here is a cubic meter!”

    I understand the operators will still often refer to how much material is being processed as “boxes per day.”

  13. paddy on 3 April 2014 at 7:19 pm

    I’m English my mid 40s, the uk “went metric” before I was born, I trained in, and only use use, metric measurements. However I work on canal boats and whilst all my plans are in metric, I still describe a narrowboat as 70 footer or 45 footer. I am also 6 foot tall and weigh about 12 stone. It gets even better when I buy sheet goods, 6mm sheets of 8′ by 4′. When it’s cold it’s around 0, when it’s hot it’s in the 90s. Juice come in litres, cider in 2 litres, beer and milk in pints.

  14. Gary Cook on 3 April 2014 at 7:46 pm

    I think imperial is a beautiful measurement. It scales up and down so well. With larger measurements in millimetres I get lost. I also find it annoys young people, which can be advantageous if required.

  15. Sylvain on 3 April 2014 at 10:13 pm

    Imperial system and US customary measurement system are quite different.

    Those sytems are “good enough” when doing LOCAL trade in a LIMITED domain:
    The grocer using only weight and small volumes.
    Selling fabric using only length;
    Milkman using only (liquid) volume.
    and so on.
    It is not a surprise that each of those local shopkeepers don’t see the benefit of the International system. Maybe they even dream that it will protect them from imported goods. But countries like China will do anything to get their business.

    In science and engineering, because its lack of coherence, it makes things overly complex without justification.

    Scientist, surveyors, boards of trade of every States could have chosen other units as long as it would have been a coherent system. So in any case it would have been different than the US customary measurement system.
    The choice has been done, the International System, is adopted by each country, except Myanmar, Liberia and … USA.
    Even the US customary measurement units are defined taking the International System as reference.
    This is resistance to inevitable change.

    We have changed our local currency for the EURO in 2001; nobody is dead.


    • Ed on 4 April 2014 at 2:28 pm

      Honestly, we resist metric just for the perverse pleasure of annoying people. It seems to be working. But, have heart because, over the years, the U.S. is inching its way to the metric system.

      All disciplines adopt units that suit them. In physics, for example, various theoretical disciplines use specialized units that are variations on SI, for sake of convenience (read, for sake of getting the right answer by not having to keep track of powers of 2 times pi, c, and Planck’s constant or various constants in E&M.) Microscopists will work in micron, nanometers, etc., rather than meters. We all get our work done. Do I prefer SI? Absolutely. Now, back to reality and getting work done, which requires me to use any units that come my way. Yes, I grumble about it, but it will never change.

      I think we should argue about whether one “makes a decision” or “takes a decision” and about standardization of English spelling, e.g., the use of “u.” If you want to beat up on the U.S. about something, you should probably focus on that “u.”

  16. John C on 4 April 2014 at 4:58 am

    Us darn “yanks” are just rebellious at heart I guess. Sylvain, don’t you mean “RESISTANCE IS FUTILE!”? No, that must have been in a star trek movie.

  17. Geoff on 4 April 2014 at 7:06 am

    I’m Australian and like Salko Safic grew up using metric so it makes much more sense to me. The problem is that a lot of wood working equipment, DVD’s, books, etc. come out of the US so we have to go through the mental gymnastics of figuring out how big something is. I prefer to work in metric because it makes the most sense to me, but I’ve also learned how to roughly approximate imperial measurements which are good enough for me, so while I can’t immediately envision what 1/64″ is, I know that 1/32″ is roughly 0.75mm and therefore 1/64″ is roughly 0.4mm.

    The most important thing in my opinion is to pick one system and stick with it otherwise you’ll just get yourself in a muddle.

    • Paul Sellers on 4 April 2014 at 9:55 am

      I think so many companies around the wold manufacture for a US market and the US is quite insulated from the need for other systems including one that unites countries like using a metric measurement system. In essence the US is more like a united Europe in that the states are a bit like countries. That being so, it has never had a need to change. I think the sciences move in metric not inches no matter where.

      • Robert on 11 May 2014 at 12:46 pm

        Paul hit the nail in the coffin.

    • Keith on 12 April 2014 at 1:32 am

      >The most important thing in my opinion is to pick one system and stick with it otherwise you’ll just get yourself in a muddle.

      Isn’t that the truth? There’s nothing more confusing than trying to constantly convert from one to the other. You don’t become fluent in a second language by translating everything, but by thinking and expressing in that language.

      There’s nothing more frustrating than an engine in imperial and a transmission in metric, a 6mm bolt 3″ long and with a 7/16″ hex head on it, a 5/16″ threaded insert with an 8mm driver socket, or a 10 mm hex head at the top of a table leg and a 7/16″ head on the shelf.

      I wish the USA would just make the jump. How are we supposed to compete in the world economy if we are different than everyone else?

  18. hervé on 4 April 2014 at 1:11 pm

    As far as I know, the main problem with metric versus impérial is they are incompatible.
    I’m a (almost) retired shipwright and I remember the first boat I built. A Wharam catamaran. Plans were both in impérial and metric and it was just fine for me but after few days, it become obvious that it didn’t make it. 1 inch=25mm. 2=51. 3=76. 4=102… You glue 4 planks of 1inch together and you end with a gap of 2mm. At the end of the first week I ordered a tape in inches and feet and learn to use it; which proved to be easier than I thought. After that I hadn’t any problem.
    Which is the best? Best for what? Does it matters? In any case, it is better to know what is all about and learning both systems gives you knowledge.
    And knowledge is better than ignorance.

  19. Kevin on 4 April 2014 at 1:39 pm

    Nice post Paul,
    As a life long (40 years) Carpenter . I am happy to use both and often do at the same time . They are just some numbers on a stick . The main advantage of inches over metric is the abilty to divide by 3 or 4 and get a mark you can actually see . I also believe it is one of the reasons many people today dont get fractions . I once worked with a bloke who used both the top and the bottom numbers on his tape measure so you would get something like 2 foot 63 as a measurement. !! Also I worked in Denmark a couple of years ago and got caught out by the Danish carpenters as a Danish inch is a bit bigger than an imperial one ! But as someone said earlier on multiple work with multiple people a storey rod is the only way.

    • Paul Sellers on 4 April 2014 at 4:34 pm

      I love this reply; 2foot 63 ‘m’ ‘n’ ‘m’s!!!!! Love it!

  20. John C on 4 April 2014 at 2:03 pm

    Paul and others are absolutely right, being from the US, I feel no need to change. When my son and daughter went through 6th grade (or maybe 5th) there was a section in math class that was devoted to the metric system. My daughter was really confused so I took her into the shop and we made a “t” square with metric measurements and our normal system of measure, all the way up to one meter or 3.3 feet. A little light bulb went off for her as she said “wow, a meter is just about what a yard is”. After she found a little familiarity with both systems it wasn’t so hard.
    On another note there are a great many tape measures on the market in the US as well as the UK that have metric and imperial on the same tape. I would definitely buy one of those if we had a total change over here in the US.

  21. Steve S. on 4 April 2014 at 7:03 pm

    There are days I think it would be easier to work wood in metric, as I’ve never been very good at fractions. But I’m not going to switch away from Imperial measurements any time soon.

    I think one reason the USA has never switched over to the metric system is the sheer cost associated with it. Take, just for one example, the interstate highway system. Let’s say we wanted to change the way we measured distance from miles to kilometers. I believe there are a good 45+ thousand miles of interstate highway in our nation. Most of those highways have a mile marker sign at every mile, one on each side of the road. That’s 90,000+ signs to replace, plus labor–just for the mile markers. The costs to replace them all would be enormous, but would provide no obvious and immediate benefit to the public.

    It’s not the idea of the metric system that bothers Americans so much. After all, we measure small engines in CCs and soft drinks in liters, and our medical and engineering professionals use metric measurements all the time. It’s the prospect of having to make such extensive and expensive changes to so many of the objects we interact with on a daily basis.

    • Paul Sellers on 4 April 2014 at 8:34 pm

      Can’t use that as an excuse Steve. In the UK we never used kilometers when we switched to metric. All signage is miles only. And…it was no less costly for the UK to change than it would be for the US. Per capita costs would be the same. Still, I am not saying there is anything wrong or right about the US retaining imperial. I like both and use both even on projects I work on.

  22. Reinoud Delporte on 4 April 2014 at 8:50 pm

    I do get confused with km and miles on a daily base. I build trucks for a living, and we build them for most parts of the world. This comes with different speedometers of course.
    To make it more confusing not every truck with right hand drive steering has a MPH speedometer. I have to be careful all the time because we have a 30 km/h speed limit on the parking lot. I find the MPH/KMH switch more difficult then the right hand drive/left hand drive switch, but I don’t drive any public roads of course.

  23. Andy Evans on 5 April 2014 at 2:26 pm

    We have rulers like that in Germany: they go up to 2000mm and fold ten times. most carpenters have pockets that carry them like you described: I often find myself reaching for it when I’m wearing normal clothes.

    I grew up with imperial and metric in the UK, but imperial is unheard of in Germany so I used metric exclusively since I came here. Frankly I’m glad: our tutor regularly tortures us by making us do equations for the amount a spacific piese of wood of a certain variety would twist in different conditions.

    How on earth do you do that in imperial? For us the amount of twisting is expressed as a percentage, so for example pine will twist 0.39% across the trunk for every 1% of moisture change in the wood. This is reasonably simple to convert to MM but how would you do that with a 12-based nimber system?

    • Paul Sellers on 5 April 2014 at 5:43 pm

      Wow! Is there a good reason that you need any of that information? In 50 years of working with every pine there is I have never known such things. I stopped using a moisture meter about 15 years ago and keep my wood in stock for as long as possible before I use it. Weight tells me most of what I need to know and micro-waving a thin sliver to see weight loss tells me moisture contents when if and when I am in doubt. Sooooo simple, especially in grams. Sometimes I leave wood on a radiator and weight before and after too.24 hours on slithers 6mil long dries to zero and i can measure the width of sa a 150 mm piece to see reduction in width.

      • Andy Evans on 6 April 2014 at 8:58 pm

        I have wondered, especially as the carpenters of the UK seem to survive without it. I think it is partly the culture of ‘German engineering’ influencing other areas, and that they really do like their training to be very high standard.

        I have used the equations to work out how deep I need to make joins for panels and things or how much a drawer slider will move in relation to the side of the cabinet etc.

        On my more cynical moments I wonder if it is just that as a rule of thumb, the longer your apprenticeship is, the better you are supposed to be paid, and apprenticeships here are a minimum of three years, so they have to pad it out with something…

        I’m still intrigued how you’d do that in imperial though, or how you work out how much glue/paint to use for an area, and especially when you have to mix different ratios and work out the conversion from weight to volume to area…

        I also have a vested interest in Metric as a cyclist because it sounds far more impressive when you give the distances you ride in kilometres rather than miles.

  24. Brianj on 6 April 2014 at 2:56 am

    I work with both in my current occupation when reviewing drawings, but the shop (in Canada) still prefers to work in imperial. As a boy, my uncle taught me to use my hands for quick references and measuring rough dimensions / estimating. my thumb at the knuckle is 1″. The span of my hand is 9″ (thumb to pinky). Comes in handy at the lumber store when rooting through the off-cuts without a tape measure lol.

  25. David Firmin on 6 April 2014 at 9:43 pm

    I am a UK educated process engineer in his late twenties. My day job is designing equipment for the oil and gas industry; vessels, heat exchangers, pumps, distillation columns etc. In order to do this I have to use a broad range of units, length, volume, mass, power, conductivity, amount, weight, pressure, temperature etc. I am frequently required to manipulate these different units in calculations and therefore I find the use of multiple unit standards ( SI or ‘metric’, US customary, English imperial specifically) the bane of my life. It’s infuriating wasting so much time converting from bbls to cubic meters to MMSCFD to gallons (UK and US!) etc. So the idea of everyone embracing the SI system (international standard) is but a distant dream to me.

    However, I recently inherited some of my grandfathers woodworking tools and am beginning to put them to use. My workbench (courtesy of Paul’s generous instruction) is complete but awaiting a workshop to sit in. I’ve also just purchased my first house and am doing some general DIY to bring it up to scratch (then I’ll build the workshop). These two recent developments have had me using units of length significantly more often than other units, specifically, lengths from 5 mm to 2.5 m. Low and behold, I frequently find myself using inches over and above my more familiar millimeters. They are easier to store in my short term memory, they are easy to divide, I rarely need to go above 100. I find it very satisfying to use in this very limited (length only) capacity.

    So professionally I long for the demise of non SI unit standards, it’ll make bringing home the bacon all that much easier. However, I’m glad that my Grandad had a 6″ square and 1/2″ chisel in his tool box as I now plan to keep them busy.

  26. Duncan Potter on 7 April 2014 at 10:13 am

    I think David and brianj between them have summed up at least one of the issues with the “international system”. Why is everything expressed in mm? Is this just as Andy Evans said to do with a cultural need for precision? Having lived in Germany and Norway I found my self wanting a standard measurement of about a foot. A meter was too big, a cm too small and a mm was something I couldn’t use or visualize. The logical measurement to use would have been a decimeter but then dividing it into halves again and again would have sounded completely ridiculous and would have ended up with fractions of centimeters. I too am now a resident of the US and completely appreciate the continuing use of the imperial system (although 20 oz pints would be nice!). My wife is Norwegian on the other hand and even after nearly 20 years, these funny, archaic but very useful measurements drive her crazy.

    To deal with moving between the systems, I regularly use simple mathematics estimating ideas that were probably the most useful techniques that I was taught at school. It basically means that I have developed my own “about” system – which works really well, doesnt slow me down and means that I can use whichever tape measure comes to hand. As long as the final focus of the cut follows the precision of whatever system I end up using – and I use that for the whole project (remember that Mars lander project disaster!) – it seems to work.

  27. Stuart on 20 April 2014 at 3:46 pm

    Little late to this party, but my Scottish woodworking pals all seem to work in imperial rather than metric, as I understand it, that’s not at all unusual for Scotland.

    • Paul Sellers on 20 April 2014 at 4:23 pm

      That’s interesting. Anyyone else have this experience?

  28. Keith on 26 April 2014 at 6:46 pm


    – If you’re a rough carpenter, you’ll work in 1/4″, fat or skinny (three feet, four and a quarter, fat)
    – If you’re a finish carpenter, you’ll work in 1/16″ (forty and 5/16 inches)
    – If you’re a furniture maker, you’ll work in 1/64″ (forty and 11/64 inches)
    – If you’re a mechanical engineer, machinist or pattern-maker, you’ll work in 0.001″ (40.172″)
    – If you’re a civil engineer, you work in hundred feet (stations), feet, tenths and hundredths of a foot. (4 +.26)