Not sure what this style was made for but it cuts nice clean circles for a old tool.

I'm pretty sure it is a steel strapping/banding cutter.

Heck yes your right that is what it's for and I cut sheet metal with it it worked good but had to take small cuts thanks.
                                   Gary s.

Can you take it apart to sharpen the blades?

It does come apart for as it has a locking nut on it, not sure if locking nuts where made back then.