Metricating US shapes
Metricating US shapes
(OP)
I was checking drawings and it had US wide flanges listed with a metric equivalent. I thought, "You don't metricate nominal sizes." Just for grins I looked in ASTM A6/A6M. Guess what? Table A2.1 shows the designation when using metric. So for example a W12x50 is a W310x74 in metric. This really doesn't make a lot of sense to me. So what is the practical use of this? Maybe order standard US shapes from a foreign mill, you specify A6M and call it out with its metric designation. Just seems confusing as hell to me. No, no, not to me personally. I can convert. I've just seen so much confusion over the years going back and forth between Imperial and metric. It seems like if you want a US shape, you should call out a US designation and leave it at that. My guess is you really don't use the metric designation to order a US shape, even if you're ordering from outside the US. Does anyone know what the thinking is here?






RE: Metricating US shapes
Sorry, could not resist.
I was reviewing ASTM A416/416M on prestressing steel recently and the same thing got my attention re ordering in metric with grade and diameter. Little easier with only two ordering parameters, but confusing nonetheless.
Damn, even Myanmar recently (2013) switched to the metric system. Only USA and Liberia left.
RE: Metricating US shapes
Until then…
RE: Metricating US shapes
An inchxlb/ft callout doesn't give me any particularly useful information when my drawings are in mm and my math is in kN. If anything, I get annoyed that the metric callout isn't mmxN/m rather than mmxkg/m, but for engineering purposes the conversion is basically just 10, so it doesn't really matter.
RE: Metricating US shapes
RE: Metricating US shapes
RE: Metricating US shapes
RE: Metricating US shapes
RE: Metricating US shapes
I recall growing up in Australia, as a very young boy and going shopping with my family to purchase fruit and veg, and meat from the butcher (do butchers even exist today?) there was a period of time (a few years I guess) whereby both lb and kg were displayed, but after the cut off date, all vendors were required to display only metric units.
RE: Metricating US shapes
RE: Metricating US shapes
RE: Metricating US shapes
The US was founded by people that left and rejected the trappings of Europe, it's religions, etc. That could have something to do with it.
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RE: Metricating US shapes
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RE: Metricating US shapes