US Patent 7896599 Hybrid composite-metal male fastener

A composite metal male fastener is provided. The metal fastener includes an elongate hollow shell made of metal. The shell includes a threaded exterior for insertion or retraction from the threads of a female fastener. In addition, the shell element includes a central bore and a radially extending flange. The male fastener further includes a core element made of a composite material including plastic, fiberglass or carbon fiber or the like. The core element fills the shell's central bore and extends from the shell to encapsulate the shell's flange to form a male fastener head.