I found it much quicker than I thought it would be. A little work with an angle grinder and a standard chisel could be modified. May not be worth the effort if only a couple of tubes are involved.

Good luck
Dave

https://www.youtube.com/watch?v=vqnMJmjtvGw This might be a little over the top, but on a smaller scale the operation is much the same. Instead of a plane round nosed gouge a " safety ripping chisel " was used by the boilermakers when they removed a tube for inspection on the ship I was on. The tool...

Russ,
You my have got it right, we'er just seeing it from a world that's a little upside down now.

Dave

Mike, I recall seeing an engine, at the Port Orchard Meet, that was built by Don Mentzer? The crosshead guide consisted of a sealed ball bearings on each end of the crosshead pin that were captured in a slot formed by spacers between two pieces of heavy square stock. The engine for a time was listed...

Thoughts on preservation Pete Culler, a regular contributor to the National Fisherman, when it was a publication with a section on history, and how they did it in the old days, wrote an article with his thoughts on historic preservation of old wrecks. His main issue was that all too many historic pr...

Steam Boat Association of Great Britain has a library of boiler designs, from small to quite large, that have passed muster with the "authorities" as I understand. https://steamboatassociation.co.uk/page-1145952 You will have to join to make use of the service. Magnificent work you are doing. I enjo...

Allan,
The drawing in Steamboats and Modern Steam Launches shows the No.6 with 3/8" valve rods. Looks like your's has had the cure applied. Have fun with the project.

Dave

Allow me to share what come to call the “Aerospace Plumber”. The incident occurred in Longview, WA in the early 80’s. A young couple complained that they had recently started to get hot water when they first opened the cold water tap (clue #1). The apartment manager called the plumber and after a lo...

Ya, Fred the demo was a bit over the top. This is the one I wanted to post, but couldn't find at the time: https://www.youtube.com/watch?v=96LwwycOhPI
I little more down to earth from a guy down under.

Dave

Check out https://www.speedtaps.com/. These are taps made for use in an impact wrench. Haven't used them myself so I can add no more to what they say.
Dave