Cutting 8-inch steel with a torch - GIF

[Frank S]

The head looks a long way away from the cutting surface. How is the gas stream held straight? Must be some high pressure behind it surely? I've hand cut 6" but I always have torch head within an inch of surface,(preheats just shy),and have found that cut gutters if torch is raised.

Yes that is all the more reason for my assumption of the type of gas being used for pressure I would suspect oxygen heat pressures in the range of 45 to 60 PS with the gas pressure upwards of the 30 to 4 PSI range while the cutting pressure probably coming in around 150 PSI. having the head that high would cut down on surface remelt
Did you happen to notice how small the kerf was relative to the thickness. To me the kerf appeared to be more along the lines of being proportional to cutting 3 inch or less . I am wondering how much bottom pre heat was used. I knew a guy who had a custom burning business back in the day of optic eye torches who had cut his mane out if a 4" cube in Chinese he owned 3 6 head and 2 3 head torches and it wasn't anything to see him burning on all 5 machines at the same time by himself. best burner I ever knew