Considering that it was the 1940s, I'm not sure how common thread-milling was. Plenty of room inside that breech - maybe a cam-operated "rapid retract" single point threading tool?
Found this page, doesn't explain how they cut the threads but does elaborate a bit on other construction features. http://www.eugeneleeslover.com/USNAVY/GUN-BARL-CONSTRUCTION-1.html A picture at the bottom hints that the female breech threads weren't cut into the barrel itself, but instead were cut in a breech housing. The barrel was attached to the housing with a regular (not stepped) interrupted thread which would be much simpler to cut - probably something resembling a shaper to make the gaps, then single-point it. On Sun, Feb 7, 2016, at 03:15 PM, andy pugh wrote: > https://en.wikipedia.org/wiki/Welin_breech_block#/media/File:Sailor_looking_into_the_breech_of_16_inch_gun_aboard_USS_Alabama_(BB-60).jpg > > I suspect an extremely specialised machine for the internal version. > > -- > atp > If you can't fix it, you don't own it. > http://www.ifixit.com/Manifesto > > ------------------------------------------------------------------------------ > Site24x7 APM Insight: Get Deep Visibility into Application Performance > APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month > Monitor end-to-end web transactions and take corrective actions now > Troubleshoot faster and improve end-user experience. Signup Now! > http://pubads.g.doubleclick.net/gampad/clk?id=272487151&iu=/4140 > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users -- John Kasunich jmkasun...@fastmail.fm ------------------------------------------------------------------------------ Site24x7 APM Insight: Get Deep Visibility into Application Performance APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month Monitor end-to-end web transactions and take corrective actions now Troubleshoot faster and improve end-user experience. Signup Now! http://pubads.g.doubleclick.net/gampad/clk?id=272487151&iu=/4140 _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
