Interlock metal hoses are manufactured by helically winding metal strips over a sizing mandrel, this strip already has minor folding which is interlocked together and forms an interlock convolution, like this continuous process a hose length is formed.
This minimum bending radius will be achieved when the convolution outside of the bend is fully open and the inside of the bend is fully closed. Considerable limited force is required to bend the hose at a bend radius, beyond this limitation of force hose gets permanently deformed.
Packing material may be inserted into the profile to make the hose pressure tight, this Packing may be of copper wire, asbestos chord, glass wool chord, etc.