Abstract: New ferrite tuning assemblies are disclosed in which a unitary ferrite shaft is covered with a nonmagnetic material to provide a peripheral working surface for coacting with unitary helical thread means in the central opening of a core element to provide axial movement, for air gap adjustment purposes, by cutting and/or deforming at least a portion of the peripheral working surface of the tuning member. Various longitudinal and transverse cross-sectional configurations for the integral male tuning member are made available by the fabrication and assembly methods taught; assembly of inductance-tunable ferrite devices is facilitated by enabling insertion of a male tuning member into the central opening of either core element in an assembly and tuning from either longitudinal end of the aligned central openings.

Abstract: New fabricating methods and products are disclosed for manufacture and assembly of tunable-inductance magnetically-soft ferrite core assemblies. Pot core type elements are pressure molded from ferrimagnetic particles having residual reactivity; unitary helical threads are tapped in central openings of compacted core elements while in the green state; subsequent heat treatment converts the green compact to a ceramic. Use of a shrink tap provides compatibility of the unitary threads with the pre-threaded male adjustment members of the prior practice. A new assembly enables use of identical core half sections; provision is made for support at one or both longitudinal ends of the male tuning member.