'Oz' Star -- Maximum Security Tattoo Parlor ... INSIDE A BANK VAULT

Former "Oz" star and Hells Angel badass Chuck Zito is opening the tattoo parlor equivalent of Fort Knox -- decking out a massive, real-life bank vault in New York with tattoo chairs, neon lights, everything.

The old bank in Monroe, NY was built in 1915 -- and Chuck tells TMZ, he's already invested over $100,000 converting the vault into a 21st century skin ink workshop.

It's pretty intimidating ... the vault door weighs 70 tons -- 140,000 pounds -- and when it's closed, it creates an airtight seal ... so Chuck had to leave the original emergency ventilator intact.