Regarding "big machining".......yes, it was expensive. To cut the bands for the hatch and three windows with the water jet was $610, but only $200 to roll them into circles. I had already purchased the steel sheet.
I could have cut the bands myself with the torch for next to no cost ( just oxy and acetylene ) or had them sheared, but I couldn't find a shear to cut 3/8 steel of this type. Although the AS 516-70 steel isn't that hard, no one wanted to risk breaking their shear. The shop also cut the circle flanges for these parts. One inch thick and 2 inches wide, 2 at 24 inch
O.D. and 2 at 16 inch O.D. plus the hatch ring at 1-1/2 inch thick by 2 inch wide and the dome lid ring at 1 inch by 2 inch.
The water jet went through that steel like butter, no heat applied, and the cut is amazingly smooth.
Total for material and labor for the three window tubes, one band at 84 inch diameter, hatch tube, and five thick rings was $2800.
Still, with all the steel here now, my total cost for the pressure hull pieces is $5200.
That is right where I had budgeted, and the quality is great.
If I had cut all this steel with my torch, I'd still be grinding the edges for several days and the steel edges would have had a lot of heat stress added to them.
Bottom line......Pricey but worth every cent.Frank D.