I can't see SWG being of any practical use to anyone except a highly skilled mathematician! Do you know how to calculate how many tiny circles will fit into one big one? And if you do find that, say, 50 pieces of wire fit into a 1" diameter tube, you've STILL got to measure the diameter to find out how big they are!
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Yep, agree wholeheartedly Dave. The weirdest thing about it is that someone at sometime thought it was a useful way of grading wire sizes…..absolutely not someone you would want to spend time chatting with in a pub I’d guess.
At least the measuring bit is easy though, you just need a hardened steel plate with different sized holes in it and see which one the wire fits in by trial and error. I’ve got one somewhere, bought as a curio for a few pence at a boot sale.Comment
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Here we go! I knew somebody must have written about the origins of those weird sizes:
This is principally about medical needles, but dives into the history of the “standard” in general in order to explain the needle sizes.
Great … but it’s not as if it’s only a confusing mess to the modern reader:There appear to be about 55 different gauges, including Twist Drill & Steel Wire Gauge for drill rod, English Music Wire Gauge, National Wire Gauge for steel wire, Standard Wire Gauge, Stitching Wire Gauge, Stubs Iron Wire Gauge, Warrington Wire Gauge, Yorkshire Wire Gauge and 28 different Birmingham Wire Gauges [3].
The section titled Industrial research explains the origin of the gauge “system”, concluding that the gauges of iron wire are “a function of the property of iron when it is drawn through a draw-plate” rather than being entirely coincidental. Once accurate measuring instruments became available in the 19th century, some wanted to redefine gauges as simple measurements of thickness (1 gauge = 1/1000 inch) or using a logarithmic scale (base 0.89, apparently …), others wanted to abandon the name entirely and just refer to thickness directly, and yet others wanted to keep the gauge (of course). Eventually, the committee looking into this concluded:—Charles Holtzapffel, a 19th century civil engineer, lamented: ‘There is little analogy, but great confusion because of all the existing gauges’ [4].
But:—Abandoning the gauge and adopting the micro-inch was rejected. The micrometer was considered too troublesome for general use because of the sensitive screwing mechanism and it would be too difficult for a craftsman or tradesman to think and speak of ‘164 thousands of an inch’ rather than ‘8 gauge’. The use of a limited number of well-defined and well-known sizes was considered important. Because the Weights and Measures Act did not tolerate fractions of inches, a real exponential scale or an average of existing scales was not possible. The gauge was to be maintained but needed to be defined as part of a perfect compromise of all the proposals, laws and international developments. It should be closely related to the Birmingham Wire Gauge. The decrements should be in multiples of 4/1000 in., thus relating to the French metric system; 4/1000 in. being an acceptable approximation to a tenth of a millimetre (0.1016 mm).
In the end, it seems like some sense prevailed, but unfortunately, I get the impression that the complaint that “it would be too difficult for a craftsman or tradesman to think and speak of ‘164 thousands of an inch’” is the real cause of the Americans still inflicting those gauges on the rest of us, even though it’s been made long obsolete by better education.This proposed standard wire gauge was discussed and amended several times. Local Chambers of Commerce feared that their own gauge would be abandoned and that Birmingham would play first fiddle.Comment
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WELL Jakko an Tim after readin your posts i dont know if im comin or goin so i think we should call you both the forums brains lol
chrisbComment
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Matron would be very interested in needle sizes that Jakko has just posted !
Next decusion will be on timber sizes , soft wood v hardwoods.US and English .
Having read all of this thread I'm more confused than normal !Comment
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I have a pre-war machinists reference ( like a Zeus, if any one knows that ) of screw threads - giving all the parameters for machining, ie major diameter, minor diameter, form & pitch - it includes exotica like French bicycle thread, Belgian watchmakers, and about half a dozen Gas threads. It also has the form & size of nuts & screw heads of all sorts - looking at these just makes me happy I only had to learn metric machining! - Although, the final apprentice machining test was to cut a left-hand square thread bolt and nut, using a tool you had to grind yourself! Just given a 25mm dia steel bar & a bit of plate. Mine fitted together, just, after thread chasing & using a pipe extension on the spanner handle!
DaveComment
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Great stuff Jakko. Just like pure mathematics, of absolutely no use to anybody, but great fun to read. The third paragraph from the end even has number scales 3, 2, 1, 0, 00, 000, etc mentioned. It shows that those that really understood the problem, the engineers Whitworth etc, wanted to go to a scale of thous, but were outvoted by the protectionists who didn’t want the brummies to take over…..as always, vested interests and protectionism ruled over common sense.Comment
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Oh, and I’ve just noticed something else…..in most uses of the arbitrary number scale things get smaller as the number decreases, so 1 is smaller than 3, and 00 is smaller than 1 etc. However, on the wire gauge scale 5 is smaller than 1, and 1 is smaller than 00. Utterly bonkers…..Comment
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Have marmite pots a dedicated gauge?
Bewilderedly yours
Andy The Sheep.:tongue-out3:Comment
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Advances in knowkledge & especially computers mean most of these are consigned to history -
Similar things that wouldn't mean anything to youngsters - log tables, sine tables, Naperian logarithms, steam tables slide rules, planometers, indicator cards & a lot more esoteric names & kit
DaveComment
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I happily destroyed my slide rule when I barely passed Materials Testing in college.Comment
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