Bel Cream Maker

I just discovered that there is such a thing as a home double cream maker!

There is a great post here: Cooking in someone else's kitchen: Another historic appliance.

I already sometimes make my own cream

I wonder if I can extend the process somehow to make double cream, take equal parts of this butter and more cream? I'll have to try it. If I can't get it to work, then I will need this handy Bel Cream Maker tool!