Hello,
Yesterday's shop pics look great-
The holes I were drilling in the mud ring are for patch bolts. These are alternatives to rivets on mud ring corners, where the tight radius inside the firebox does not allow room for a rivet. A patch bolt is threaded about half way through the depth of the mud ring, then headed into a countersunk hole which will be prepared on the outer sheet. There will be 8 on our mud ring.
The flexible crown stays were not on the original boiler, but are used here as an alternative to crown bars (which were employed on the original boiler). ASME still allows crown bars- but with stringent stiffness requirements for which there was extremely limited room on this small boiler. We also called the FRA inquiring whether crown bars are legal with them (the rumor is that they are not)- their engineer in DC could not find such a law but could not say with certainty that there may not be some old ICC rule against it.
So the flexible crown stays allow for a flexible crown sheet as the crown bars essentially would have done. BRV bought the flexies, sleeves and caps pre-manufactured of code material from the Strasburg Railroad- what a great resource those guys are for staples of the steam locomotive industry but oddities anywhere else. They just want to help all they can...
In Stephen's photos you can also see the home-made bronze washout plugs we had to make. The code doesn't tell you you have to make them yourself- but no one supplies them of code-accepted bronze material. 1+1= ... As such we made them longer and heavier than standard bought plugs to simulate the look of older plugs and give them more life.
Boothbay has been great to work with us to make this boiler something to be proud of, instead of something that just makes steam. We're now pushing to get it out of their hair- they have a great many other projects fighting for attention and floor space. It'll be a great incentive having the boiler at Sheepscot Station to hammer out the rest of this project.
see ya
Jason