I speak from experience....this is a scroll
form made and used by a blacksmith.
A piece of iron is pushed into the center
and wedged by the form. It is them bend
around the form to form the curve.
Note that all the welds or brazing is on the
inside of the curve, out of the way.
If the material is thin it is bent cold. If it's
hot, it's bent hot. A two prong bending fork is
used to encourage the iron to follow the form.
I have made several of these type of forms and
used many. Believe me, I know of what I speak.
Typically made from scrap and all a little different
The cross bar near the top is held in a vise.
It is an intersting find.
Hay2