Posted by: Rolly
Yes they did Peter. Exactly when I’m not sure. It was an interesting way in how they prepared the tube sheet for the welding. They milled a recessed grove around the hole for the tube to form a false tube. Then when the tube passed through it looked like one tube inside another. They then gas welded the edge of the tubes together. This was only done on the bottom, the top was rolled in.
I am attaching a PDF drawing as well as a photo.