Today I made the smoke box cover for the vertical boiler.
I decided to try a different method for making the 20 degree conical shape. Previously I have beaten or tapped or hammered the shape. This time I decided to press the annealed 3mm thick copper into the desired shape. It worked!
I needed a 20 degree conical shape. For various reasons I decided to use 3mm thick copper.
So firstly I turned a male and female form in hardwood.
Then I cut out a circle of 3mm thick copper plate.
Then I pressed the shape between the forms in my 20 tonne hydraulic press.
It worked perfectly! In one go. But the flange still needed beating with a hammer, after multiple annealings.
This is a staged shot of the pressed copper between the male and female hardwood forms.
The female form on the left, and the copper, already flanged over the male form.
The male form
Prying the copper dome off the male form
This is the smoke box lid, shaped and turned, ready to be attached to the boiler cylinder. It looked a lot nicer after a soak in sulphuric acid.
This is how it will look with the chimney attached.