Even mid century modernists and even earlier jewelry artists used prefab pinback findings. I must go centuries back in time to create a fibula pin brooch without a "pre fab hinge", instead providing a primitive unilateral spring action pin, thereby requiring that the wearer just barely open it 1/4" just enough to allow the fabric. Much more convuluted and complicated curves than mid century modernist examples. Could even be considered a Fibula, as it is made from ONE piece of silver!