3D‑printed three‑jaw self‑centering knob‑operated locking mechanism, primarily designed for the rapid clamping of cylindrical shafts or rods, is a lightweight, cost‑effective manual clamping device. When the knob is turned counterclockwise, the three jaws move outward along arcuate grooves, increasing the central bore diameter to accommodate the rod to be clamped.

Turning the knob clockwise causes the three jaws to simultaneously retract toward the center, evenly gripping the rod at three points to achieve self‑centering alignment while delivering reliable clamping force.