Apparatus and method of molding a biconical socket

A method of molding a biconical socket (10) of precise length (L or L') and concentricity characterized by the steps of

• inserting a mandrel assembly within a mold cavity, said mandrel assembly having a first mandrel member (20) with a frustoconical end (22) and a second mandrel member (21) with a frustoconical end (23), said frustoconical end of the first mandrel member having a pin (24) coaxially extending therefrom, said pin being slidingly accepted by a centrally disposed hole (25) in the frustoconical end of said second mandrel member to permit abutment, said pin being fabricated from a material having a thermal coefficient greater than that of the mandrel member material,
• heating a preselected mold material to a predetermined temperature sufficient to soften the mold material as well as heat the mandrel material to thereby substantially reduce the clearance between said pin and hole and injecting said mold material into said mold cavity, said mold material being injected into the mold cavity under pressure to produce opposing forces (F, F') parallel to the longitudinal axis of said mandrel members thereby forcing said mandrel members slightly apart,
• removing said mandrel assembly and the molded biconical socket from said mold cavity,
• disassembling said mandrel assembly from said socket,
• post curing said biconical socket at a preselected temperature and time to post cure the material, and
• soaking the biconical socket in distilled water for a sufficient time to saturate said mold material.