Brake line flaring tool that actually double flares steel line?

I found an older National brand at a flea market and it works great, albeit a lot of pressure is required.

The issue is the Manufacturing tolerance on the clamp.

Newer cheap ones don't hold the tube and the force required to "double" the flair pushes it out the bottom and/or deforms the flare.

I use the double flare button as a guide to know how much tube to leave above the clamp.
Just a little (maybe 1/32") more than the height of the button outside diameter.