6″ Vertical Boiler- the Firehole
The firehole is the opening where coal is shovelled into the firebox. It is oval shaped, and is exposed to the boiler pressure. It is made from thick copper tube. Oval holes must be formed through the boiler wrapper and the firebox wrapper.
The first task is to shape copper tube which is circular, into oval shaped tube. I decided to make an oval shaped split wooden form and to compress the annealed copper tube with the form.