I’m ready to make the end plate formers for my small horizontal pot boiler. The body tube is 1.625” od, and 1.512” id, thus a wall thickness of .056”. I have both aluminum, and oak available for the formers. Are there any hard/fast rules or formulas for making the formers? With either material, I plan to have a center hole for a mandrel to turn them on. I’m leaning toward turning the former out of aluminum, as I have enough copper tube for a couple more.

I’m also making the end plates from pieces of the tube, so the end plates will be .056” thick. What would be the minimum radius for the flange? How wide should the flange be?

I’m following Stan Bray’s design Boiler # 1, in chapter 14 of the book “Making Simple Model Steam Engines”, but I couldn’t find 2” or 50mm tube. I assume the former diameter would be tube id – (wall thickness x2) and the blank disk should be a diameter of tube id + (flange width x2), with some allowance for the radius of the flange bend.

Last question, which is the best orientation for the end plate in the body tube, flange pointing in or out? Why?