External Threading

[Barbells] are attached to [beads] via threaded rods. How they attach can vary.

There are two main kinds of threading used in the [body modification] industry. The top drawing shows an internally threaded barbell, where the bead screws into the bar. The bottom drawing shows an externally threaded barbell, where the bar screws into the bead. A subtype of external threading is step-down threading, where the threaded portion is of a smaller gauge than the main stem of the barbell - this can help prevent the threads catching on the [fistula] during insertion.