AO Knuckle Joint (Threaded)

The Rebco AO Knuckle Joint is a ball-and-socket articulating connector that provides up to 15° of angular flexibility within the wireline tool string. It is typically placed immediately above the working tool (running tool, pulling tool, or service tool) to allow that tool to align freely with the tubing bore rather than being held rigid by the tool string above. This angular compliance is particularly important in deviated or corkscrew tubing conditions, where a rigid tool string will bind against the tubing wall, preventing tools from reaching their target, reducing jarring effectiveness, or making it impossible to latch or unlatch downhole controls. When a significant deviation is present, additional knuckle joints can be placed between the stem and jars, and at every connection in the string as required. It is important to avoid placing excessive knuckle joints in the string; too many knuckle joints can redirect downward jarring force sideways into the tubing wall rather than downhole, reducing jar-down effectiveness. Every knuckle joint should have a fishing neck on the lower body to assist recovery in the event the ball-and socket connection separates downhole. Available in standard threaded connections from ⅜"–2½" OD, with optional double fishing neck.

Critical: A knuckle joint is not a substitute for a swivel joint. A swivel provides rotational freedom under load with only 1°–5° of lateral movement. A knuckle joint provides 15° of angular movement but cannot rotate under load. If a knuckle joint is used where a swivel is needed and the wire parts, the rope socket fishing neck can fall over against the tubing wall at an angle, making recovery with a pulling tool extremely difficult or impossible.

AD Knuckle Joint (RQLD)

The Rebco AD Knuckle Joint is the RQLD double-shoulder quick-lock version of the Rebco AO, combining the same 15° ball and-socket angular flexibility with Rebco's heavy-duty Quick Lock System connection. Available in RQLD connections, 1½"–2½" OD.