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Metric and SAE in Europe

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  • Metric and SAE in Europe

    I have two questions for our continental European friends.

    1. In North America we have 1/4", 3/8", and 1/2" size drivers for socket set. What are the metric size drivers that correpond to those sizes?

    2. How difficult is to source SAE fasteners say in Germany or France? In Canada where we're suppose to be metric, most fasteners are still SAE, although a well stocked hardware store will have the more common size metric.

  • #2
    Originally posted by rotate
    I have two questions for our continental European friends.

    1. In North America we have 1/4", 3/8", and 1/2" size drivers for socket set. What are the metric size drivers that correpond to those sizes?

    2. How difficult is to source SAE fasteners say in Germany or France? In Canada where we're suppose to be metric, most fasteners are still SAE, although a well stocked hardware store will have the more common size metric.

    1/4", 3.8, 1/2, 3/4 and 1" They are even advertised in those sizes.

    Thats right although the world went metric we stayed with imperial (SAE) measurements for the drive dimensions. I guess it was the only way to have interchangeability when working on things during the changeover period - could you imagine how bad it would have been to have to differentiate between a 12mm drive and a 1/2" (12.7mm) drive in your toolbox?

    So you have highlighted a fault in the metrification process.
    Cheers

    Craig
    Brisbane Australia

    Comment


    • #3
      I have never seen a metric sized socket or drive.
      But they may exist (extinct?), I don't now.

      There are other things that are either measured, sold or even made in inch sizes here in Europe.
      Tire and rim sizes (only diameter that is) are made as e.g. 17", although some rare examples of metric tire sizes exist.
      I know Michelin made a metric tire for certain Ford (Granada) and Citroên cars.

      Monitors and TV screens are still measured in inch sizes.

      Boats are often measured in foot (feet?).

      And there are lots of other things that are often sized in inches, at least unofficially or as an old habit from the old days (nails and lumber for example).


      .
      Thomas

      Problems worthy of attack prove their worth by hitting back
      - Piet Hein

      Comment


      • #4
        Conversion

        The "inch" square drives are pretty well universal - 1/4", 3/8". 1/2", 3/4" etc.

        They were and are so common that it was and is not practical to "metricate" them to the "metric preferred" sizes - ie 6mm, 10mm. 12mm, 20mm etc.

        This "non-conversion" is actually a conversion in the "Metric" world we live in - Australia is "metric" as well.

        The apparent "non-conversion" is actually a "hard conversion" where the "inch" size is converted to an exact metric size (ie inch x 25.5 = mm).

        So, in the "metric world": the "hard conversions" are: 1/4" = 6.35mm, 3/8" = 9.525mm, 1/2" = 12.70mm etc. etc.

        So-called "soft" conversions are where the "inch" size is substituted by a size from the metric "preferred series".

        Inch sizes as well as metric are available in OZ - not all and not all are cheaper etc. We still use BSW, BSF, SAE, NF, NC etc. most of which are readily available.

        Another good example of the "hard" conversion to exact metric equivalent sizes is/are the NMT/NST milling machine tapers etc. These are a "hard" (ie exact) conversion of inch to metric and have been adopted and published as an ISO standard:

        http://i200.photobucket.com/albums/a...ine-taper5.jpg

        And FWIW, the inch is defined as both 0.9144 metre and 25.4mm - so the inch and all of its derivatives are in fact metric.

        http://en.wikipedia.org/wiki/Inch

        International inch
        In 1959 the United States and countries of the Commonwealth of Nations defined the length of the international yard to be exactly 0.9144 meters[1]. Consequently, the international inch is defined to be exactly 25.4 millimeters.

        The international standard symbol for inch is in (see ISO 31-1, Annex A). In some cases, the inch is denoted by a double prime, which is often approximated by double quotes, and the foot by a prime, which is often approximated by an apostrophe. For example, 6 feet 4 inches is denoted as 6′4″ (or approximated as 6'4").
        FWIW, the pound mass and pound force are similarly defined in metric units.

        The international avoirdupois pound defined as exactly 453.59237 grams.


        The pound or pound-mass (abbreviation: lb, or sometimes in the United States: #) is a unit of mass used in the imperial, United States customary and other systems of measurement. A number of different definitions have been used, the most common today being the international avoirdupois pound of exactly 453.59237 grams.

        The word pound comes from the Latin word pendere, meaning "to weigh". The Latin word libra means "scales, balances" and it also describes a Roman unit of mass similar to a pound. This is the origin of the abbreviation "lb" for the pound.

        Comment


        • #5
          We used inches and other non-metric units of measurement here in Norway too, before the metric system took over.

          But we had our own definition of foot and inch.
          A foot (fot) was 31.375 cm, and an inch (tomme) was therefore 2.6145833 cm.
          But I read on Wikipedia now, that there also was a decimal inch =3.1375 cm, never heard of that before.

          Norway joined the metric convention in 1875, but the inch was used far into the 20th century.


          .
          Thomas

          Problems worthy of attack prove their worth by hitting back
          - Piet Hein

          Comment


          • #6
            The system is as clear as mud.
            When we went to so called metric system our saw mills sold timber by the foot but supplied the metric equivalent.

            At the time I was house building(my own) and needed some 8 foot timber lengths for the scaffolding timbers which had to be 8 foot in length so you would pay for the siad 8 foot and get 2.4 meters which is only 94 1/2 inches so 1 1/2 inches short not good for fitted scaffolding so I had to buy 9 foot lengths and cut them to the 8 foot lengths. Just could never get my head around the fact that I paid for the timber by the foot but never got it!!!
            Peter
            I have tools I don't know how to use!!

            Comment


            • #7
              Same here

              Originally posted by ptjw7uk
              The system is as clear as mud.
              When we went to so called metric system our saw mills sold timber by the foot but supplied the metric equivalent.

              ...................................
              ..................................
              ..................................

              Peter
              Same here in OZ Peter.

              The trick was to buy "10 foot" (3.00 metre), square the ends if needed, cut to 8 feet, (2.438 meter) and use the off-cut for blocking or "noggings" (between studs at mid-height).

              Worst was the standard doors which went from 6'-8" x 2'-8" (2.032 x 0.812 metre) to 2.040 x 0.820 metre. It wasn't much but it was a PITA for a retro-fit. "Standard" windows for a retro-fit were the same.

              It was common for Builders to go into a Building Supply shop and ask for "6 metres of 4 x 2"!!

              Comment


              • #8
                I wonder why the U.K. still posts distances in miles, and speed limits in m.p.h.
                Was metric tried, and found confusing?
                Allan Ostling

                Phoenix, Arizona

                Comment


                • #9
                  --------------------------------------------------------------------------------

                  I wonder why the U.K. still posts distances in miles, and speed limits in m.p.h.
                  Was metric tried, and found confusing?


                  It`s because the UK goverment do not want to stand the cost of replacing all the road signs.They recently got an exemption from the European parliament,so no longer have to change them.

                  Comment


                  • #10
                    Sour grapes

                    Originally posted by Mark McGrath
                    --------------------------------------------------------------------------------

                    I wonder why the U.K. still posts distances in miles, and speed limits in m.p.h.
                    Was metric tried, and found confusing?


                    It`s because the UK goverment do not want to stand the cost of replacing all the road signs.They recently got an exemption from the European parliament,so no longer have to change them.
                    Thanks Mark.

                    I rather liked the version of the reason which was that the "Brits" who (thought they) "owned" the "Imperial" (inch, yard, mile, pound, ounce etc. etc.) and who never thought much of the French ("frog-eaters" the Brits called them).

                    The Brits regarded metrics as a Gallic/Gaulist (General deGaulle?) (sp?) "plot".

                    If so, it was just the Brits being Brits and having a case of (non-French) "sour grapes".

                    Comment


                    • #11
                      Metric and SAE

                      Mark is over simplifying the situation. Understandingly, because we are used to driving on the 'wrong side of the road'!
                      Many countries in Europe shared the same but when the Nazis overan many counries, they were obliged to do as their masters bid. Sweden actually changed voluntarily- on a quiet Sunday! So much for ancient history but the posher French cars of yesteryear were Right Hand drive. The answer was so that the chauffeur( the stoker come driver) could hop out and open the door for Madame- on the proper kerb side. There was also 'wrong way doors' to gather passing females on route. there was aslso the Mercedes 'gunsight' three star which aided Belgian drivers( but I jest)
                      The English( and I suppose the Scottish) reason for the wrong side of the road dates into when gentlemen escorted ladies on the left so that their sword hand was free( I jest not)

                      Regarding the SAE thing, there was an interval when the Brits went from Imperial( you know, Queen Victoria 'verrry fine chap') and 'Ou est le papier' sung to the old French hymn tune of Marseilles.
                      We now have gone 'dismal' and have 'libras' with decimal bits and we weigh things in them thar grammes and pounds and ounces.

                      On another channel, I was commenting that the Brits have been enjoying complicated metrication since the War( to my knowledge). However, the French have- God save their grenouilles- have been using English miles as a hangover from the Romans whilst the Spanish have Imperial plumbing.
                      That is left over from the 'one pipe system' which delivered fresh drinking water by day and returned the 'night soil' at night.

                      Well, you you could have found the important bits in Google. Mine, surprisingly, is quite accurate. Now the Romans had '4 feet 8 and half inches' and so do you and me but Isambard Kingdom Brunel who was sort of French, had different ideas! That is your homework for the week!
                      Bye!

                      Norm

                      Comment


                      • #12
                        It`s because the UK government do not want to stand the cost of replacing all the road signs.
                        No need to replace signs. Here they just had piles of peel and stick labels made to change only the the part that needed changing. A 30 mph sign became a 50 kmh sign.
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                        • #13
                          metric and sae

                          Agreed Evan but Canada has Right Hand Drive cars. To go 'into Europe' means changing Road junctions, traffic lights and all sorts of simple things like changing the side that the pedals and the steering wheel go on.
                          I have a 'Cuddy Hander' named after St Cuthbert who was left handed but that is in Spain not the UK.

                          It's all difficult here. In Canada apart from sticky labels, all that was left was to teach the French Canadians to speak----------French.

                          Oui, ca va?

                          Norman

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                          • #14
                            Never happen.

                            But then, was it Churchhill that said "The English and the Americans are two great peoples separated by a common language"?
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                            • #15
                              Usually credited to Oscar Wilde.

                              Others claim George Bernard Shaw.

                              Bertrand Russell, Dylan Thomas, and Winston are also sometimes blamed for it.
                              Last edited by rantbot; 02-12-2008, 11:22 AM.

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