About 30 years ago I worked at a restaurant, in the back was an electrical panel with 2 breakers and no cover for the breakers. Fire Dept finally flagged it as an offense, Store manager asked me to fix it. I had a local sheet metal shop make me up a panel out of 18 gauge steel. I carefully marked out the opening for the breaker, then, using a mini hacksaw blade chucked into my Sears 20" "Professional" scroll saw cut out the openings. As Fab4 has stated, loud, really really loud ( foam earplugs + over the ear muffs; and it was still loud). Finished the monstrosity and installed. Done and passed all inspections since.
It was cut out of 1/8 plywood, but I cut a butterfly valve for a carburetor once.
Not on purpose but I have cut pin nails used to hold alignment on stack cut patterns. Its tough on the blades but they cut.
I have cut, steel, plastic, acrylic, copper, leather. And the list goes on.