Can ends sorted…sort of
There was a time, not so long ago, when I believed that all ideas just needed to be shouted aloud and this would be enough to get the great ones to stick. But times have changed. Some of my fellow vloggers and citizen scientists seem to think nowadays that scientific evidence can simply be denied by juxtaposing it with unchecked reasoning, often based upon unclear sources, that repeated other unclear sources, that were based upon nothing at all. And it works, too! When marketed smart enough, even bad ideas can be made to stick. Flat earth theory is a great example. Shouting ideas can become a worrisome practice fast, if it does not evolve to something more profound. So, if we want to gain true knowledge in our Pull Tab Archaeology project, we need to check our sources before we start to shout. We need good sources, properly referenced and we need them bad.
How does this relate to our main topic of today? Well, a lot actually. When I look online for information on can sizes that relates to dating, my first attempt would be to go to be manufacturer websites, like Ball, Ardagh or CanPack. These website are, however, not designed for historical purposes. Most websites do hold a brief corporate history – for what its worth in a branch flooded by hostile takeovers – but accuracy is not their strongest point. Old products are never shown, dates and numbers can be off, or just copied from Wikipedia, at least, that’s my impression. Corporations have incredibly bad memories, so it seems. They know what they sell today, but ten years ago??? A mystery! A nice incentive for contemporary or historical archaeology, btw.
So, looking into the genealogy of cans, I needed to look for different sources. This did not make it any better, but it did make me happier. Especially when I found this page: https://www.sizes.com/home/cans.htm
Sizes.com: an ‘archaeological internet artifact’
So, how weird it may seem, after seeing so many hypermodern websites of billion-dollar-companies in the beverage can industry, the one vital clue about can sizes which I have been looking for for ages, I found on this page ONLY: the explanation of the three digit number that signifies can diameter!
The three digit can end code explained and dated
All sites of the biggies are clear in their offer: if you need any 202s, 204s, or even even 200s can ends for your innovative raw juice project, give em a call, and they’ll send you 400.000 copies within 4 weeks! But nowhere on their websites do they explain -at least as far a I looked- what these sizes mean!
Sizes.com does. The first digit in the three digit code is the number of whole inches in the can-end diameter. In almost all current beverage cans this is ‘2’ as all standard cans are just over 2 inches wide.
So much i knew. It were the last two digits that remained a mystery to me until yesterday. Being European, I would expect the last two digits to be the decimal fraction of an inch. But no, not in inch-, foot- and mile-minded USA. 😉 The last two digits actually stand for the number of 16ths of an inch!
So, if a can end is coded 202, which the current standard in the West (330 ml and 12 or 13 oz cans) this indicates that the ends’ diameter measures 2 whole inches and 2/16th of an inch!
Lo and behold, after three years of Pull Tab Archaeology we now have a way of connecting manufacturers ‘code-language’ to measurable sizes from field data! And it works: 2 + 2/16 inch = 2,125 inch or 5,40 cm! And as you can see in the picture, our measurement on a recent Ball 202 can-end is only 0,005 inch off! I think machinist would call that ‘5 thou difference’ and that’s an excellent measurement for the average pull tab archaeologist with a 10 Euro caliper! “It Vurks!”
Still, the one source is a sketchy source, because it is unreferenced. But we can now start to compare it to field data and we have no reason to doubt it yet!
|Industry end code||Inch||Centimeter||Dating information|
|6,8||Unsure if this is a truly different size, but cola-dosen.de reports that the original straight can can-ends are 68 mm in diameter and thus wider than the 65 mm of the necked drawn and ironed 2-piece can from the 70s, in other words the 209 can-end.|
|209||2,56||6,52||(note row above this one) Early cans! At least back to 1960s (if not 30s) and up to mid 1980s. Might still be in use as odd size for marketing purposes or in non-European markets.|
|206||2,374||6,03||1987 onward (says one unchecked source, needs more data)|
|204||2,25||5,72||1991 onward, says one unchecked source.|
Little data on this end in our project / not in our collection. I think this can was not produced for European markets.
|202||2,125||5,40||1990s onward (one source says 1991)|
|200||2,0||5,08||mid 1980s onward. European market|
Point used to indicate decimal position (European style).
Check elsewhere on this site if this May 2020 table is still what we believe to be true!
Edit the next day: Only now I realise that this is the same division at the rims and tubes of bicycle-wheels… that figures. It is called the dyadic-rational. Funny that I never thought of that before. For me, as a European, the impirical system is just so weird.