Thread cutting taking place on the tubeplate ahead of tubing. A general view of the tubeplate.
Close up view of the thread cutter.
At the smokebox end....the shaft on which the thread cutter is positioned runs through to the smokebox tubeplate, where a bush is inserted into the flue tube hole. This ensures the threads at the firebox end are absolutely aligned to the smokebox end.
The firebox crown, showing the row of crown stays to be replaced.