See Locking Trunnions in Action - Carr Lane Mfg. Co.

Trunnions from Carr Lane Mfg. Co. are rugged, precision bearing mounts for revolving fixtures. Ideal for assembly and welding fixtures, and any other applications where the part must be accessible from all sides. Usually used in pairs, one locking Trunnion and one revolving Trunnion, to distribute the load between them without bending forces. The locking version, shown here, has a friction-cone mechanism that stops the rotor at any angle by tightening the knob handle (loosen knob again to unlock). The revolving version has a free-rotating bearing at both ends of the rotor shaft, with no locking mechanism. Made in USA.