I did not expect these mounts to require a third day session, and they are still not finished!
I discovered that two of the drilled holes in each bracket were in the wrong position, by approx 1mm. That is a really bothersome error, because the correct position includes half of the existing hole.
I managed the problem by threading the errant holes, and Loctite gluing in some threaded rod. Each rod was trimmed flush with the surfaces. Then drilling the new hole, partly through the Loctited metal patch. That fix worked well.
THE TRUNNION PINS.
The pins hold the trunnion caps in place. And they took another whole day to make and install. Ah…. just as well I enjoy all of this. They are tiny, and I spent at least 50% of the time looking for them on the workshop floor after accidentally dropping them on several occasions.
So, apart from polishing riveting and painting, I think that the trunnion mounts are finished.
Now planning to make the gear train for the carriage positioning on the chassis, and the pinion, quadrant gear, and bevel gears for the barrel elevation. We are currently in level 3 lockdown for Covid containment, with level 4 looking likely any day, so obtaining brass for the biggest gears is difficult. I am considering workarounds. Apparently community anxiety and depression, family violence, and even suicides are mounting. When I am in the workshop I am in a different world, thank goodness.