A truck-mounted hydraulic crane had a horizontal thrust bearing with one race attached to the truck and the other to the rotating crane. The outside race of the bearing was driven by a pinion gear, and it is through this mechanism that the crane body rotated about a vertical axis. The manufacturer welded the inner race to the carrier in a single pass. After several years of service, the attachment weld between the bearing inner race and the turntable failed in the area adjacent to the heat-affected zone. The fracture zone where there was the greatest tension was heavily...