Talk:Panzergewinde

Why was VDE (apparently) catering to inch-based preferred numbers for TPI? Dunno.
It made me curious why Gangzahl pro Zoll (threads per inch, TPI) would be a nice round number on a German standard. I don't currently have any answer for that. I even pasted the PG table into Excel and threw in some unit conversion columns (for each existing column) to see if I could infer what they were working backwards from (and maybe why) regarding conduit OD and ID and cable DIA. I couldn't see any patterns in the data. Perhaps VDE was writing a German standard that would interchange with an existing British standard in common use in Germany at the time? I ain't enough of a pipe thread guy to know without digging further. An interesting daydream, though. — ¾-10 18:42, 26 November 2010 (UTC)


 * The other day I had an interesting insight about this fascinating topic that probably no one but me thinks is fascinating. (That is, the presence of a nice round TPI value on a German standard created long ago [probably pre-WWII?] despite not-nice-round inch conversions of the other values [OD, ID, etc].) Here's the insight: Picture this. It's 1908 (or some such early era) in Germany. The land is filled with lathes and milling machines. A significant fraction of this machine tool population is imports from the U.S. and U.K., who've done a nice job of exporting the crap out of their machine tools since many decades ago. You can turn, bore, mill, or file any nice, round millimeter dimension that you want using your imported machine tool with its nonmetric cross-slide leadscrews; simply cut-and-try—the ancient way of the machinist, toolmaker, millwright, and carpenter. But what you cannot do is get around the fact that your lathe's main (screw-cutting) leadscrew has a nice, round TPI value. Oh, you could, if you had the 127T metric transposing gear, but you probably don't have that, because you got in on the ground floor of machine tool buying (barely afforded to buy one at all), and 127T metric transposing gears were one of the upgrade options that you didn't buy. Which was a reasonable choice, because the markets you were trying to serve are so darn filled with large pockets of TPI demand (the export market because it's all the U.S. or U.K. want to buy; the domestic continental market because everyone lives in a world surrounded by imported machinery with nonmetric parts that need nonmetric repairs). Your countrymen with continental-built lathes probably have metric leadscrews, but if they do, they probably also have transposing gears to cut TPI threads, because the markets they're trying to serve are so darn filled with large pockets of TPI demand (the export market because it's all the U.S. or U.K. want to buy; the domestic continental market because everyone lives in a world surrounded by imported machinery with nonmetric parts that need nonmetric repairs). Therefore, if you're the VDE, looking to create a real-world standard that herded cats countless private-sector makers of conduit, cable glands, hardware, and equipment will actually rally around, you can spec your nice round mm values for OD and ID, but maybe you'd better spec a thread pitch that can be cut as a handy multiple (ie, change gear ratio) of an English or American leadscrew pitch. Voilà! Q.E.D. Now, whether this bedtime story reflects the reality is completely unproven. But it sure does have some shiny speciousness if not. Now—Is the kiddo asleep yet? — ¾-10 23:33, 30 November 2010 (UTC)


 * Sounds plausible. ASTM writes their standards to match the tensile strength of our strap and the weld strength of our sealing systems. But then again that's completely arbitrary, unlike your situation where all of the trees match the forest except for one. Sounds pretty plausible to me. Now you just have to prove that UK and US export to Germany were as great as you think (or dream) they were. Wizard191 (talk) 00:00, 1 December 2010 (UTC)

References to DIN EN standards
I have changed them to EN. EN denotes a CEN/CENELEC standard, common for all european contries, DIN EN or BS EN are the national versions which should be identical —Preceding unsigned comment added by 80.34.24.48 (talk) 16:15, 30 November 2010 (UTC)