The problem you have is with the "centrifugal force" language. This term doesn't only apply to butterfly knives, but to any knife that can be opened throught the use of gravity or centrifugal force.
The term was originally directed to the "gravity knives" that were the autos of WWI (II?)...
"My wife put it away somewhere and I never found it again."
That's what happened to the last guy that had it!
5,000 years from now, somebody will be walking by the ruins of your house.............
I was just referring to the big loop mod to the lever like Chuck Connors had on the show. I've seen em on gunshow levers, so I know it's available somewhere.
Mostly for show, but with a little practice you could have the bali of Marlins. Spin it!