See this picture. This frame hold some kind of blade. It is similar
To a hacksaw. But is only about 5 inches. I wonder what kind of
Saw blade would fit?

Coping saw... it uses very small blades for cutting intricate patterns in wood.

Basically like these... only yours was made back when they made things to last.

http://images.rockler.com/rockler/images/99847-01-200.jpg

Oh a coping Saw Thanks