From: muratlanne@gmail.com   
      
   "David Billington"  wrote in message news:10al2im$r408$1@dont-email.me...   
      
   On 20/09/2025 00:01, Jim Wilkins wrote:   
   >As the threading label was missing I made one up as a spreadsheet and   
   >printed it. ... In Britain pipe thread pitches are different and the   
   >spreadsheet won't be correct.   
      
   If you're referring to BSP threads why mention it as they're inch   
   threads and typically differ from NPT by 1TPI, excepting 1/2" and 3/4"   
   which have the same pitch. The ISO pipe thread is BSP.   
      
   ----------------------------------   
   The standard thread pitch choices on a US Heavy 10 lathe 70 speed QC gearbox   
   are:   
   8, 9, 10, 11, 11,5, 12, 13, (13.5), 14, (15),   
   16, 18, 20, 22, (23), 24, (26), 27, 28, (30),   
   32, 36, 40, 44, (46), 48, (52), (54), 56, (60)   
   64, 72, 80 ...   
   The missing pitch for BSP is 19 for 1/4" and 3/8".   
   (#) indicates an unused multiple of another standard, as each row is twice   
   the one above. I left out the top row which is half the one below, 4 to 7.5,   
   and the two lowest rows which are for fine feeds, driven from a keyway in   
   the dual purpose leadscrew.  The lathe has a banjo for change gears but the   
   leadscrew drive still has to go through the gearbox.   
      
   US pipe threads standards were established before there was much steam   
   engine trade between Britain and the US. We imported a few British   
   locomotives at first, then diverged because we weren't as limited by your   
   loading gauge and right-of-way restrictions, or Watt's objection to high   
   boiler pressure. Inside-the-frame cylinders and one pair of very large   
   driving wheels never caught on here. Our steamboat engines developed   
   independently from Oliver Evan's designs.   
   https://en.wikipedia.org/wiki/File:MR_4-2-2_673,_Rocket_150,_Rai   
   hill,_May_1980_Slides184_(9859805644)_%E2%80%93_edited.jpg   
      
   https://www.detroitnippleworks.com/pipe-thread-standards/   
   "The history of pipe and pipe threading dates back to development in 1820 by   
   Robert Briggs at Pascal Iron Works of the Morris Tasker Co. Located in   
   Philadelphia PA, Robert created his first gage in 1834 to examine internal   
   pipe threads."   
      
   https://railwaymatters.wordpress.com/2019/11/03/north-american-steam/   
   "At around the end of the 18th and beginning of the 19th century, it was   
   deemed an offence by ·the government of the day to transmit any information   
   about the development or use of steam power to North America."   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)