A method of making a hermetically-sealed feed-through device includes inserting an elongate conductor or conductors within a hollow portion or portions of a plastic insulator body and inserting the plastic insulator body within a hollow outer jacket to form an assembly. At least one of the conductor or conductors, insulator body, or jacket of the assembly has a plurality of circumferential grooves. Thereafter, the assembly is crimped and/or is swage-crimped at ambient temperature to cause the materials of the conductor or conductors, insulator body, and outer jacket to be displaced or extrude into the grooves thereby creating mechanical interlocks between the conductor or conductors, insulator body, and outer jacket. Additional methods and feed-through devices made by the methods are also disclosed.