It is important to clarify upfront: "Franz Crack" does not refer to a specific model of pen. Instead, it is a collector's term for a known that affects many Franz fountain pens produced between the 1930s and 1960s. What is the Franz Crack? The Franz Crack is a hairline fracture that appears on the titanium or steel nib of certain vintage Franz fountain pens. It typically starts at the base of the breather hole (the small hole in the center of the nib) and runs toward the tip (tines) or toward the base of the nib where it enters the grip section.