A friction stir welding tool includes a stir pin, a pin holder, and a housing. The pin holder supports the stir pin to rotate with the stir pin around a rotation axis of the stir pin and has a front portion and a rear portion opposite to the front portion along the rotation axis. A tip end of the stir pin projects from the front portion. The housing houses the pin holder such that the pin holder is rotatable relatively to the housing. The tip end of the stir pin projects from the housing. The housing includes an engaging portion engageable with a spindle frame of a machining head such that the rear portion of the pin holder is attached to a rotation spindle of the machining head to rotate the pin holder. The rotation spindle is rotatable relatively to the spindle frame.

A friction stir welding tool includes a stir pin, a pin holder, and a housing. The pin holder supports the stir pin to rotate with the stir pin around a rotation axis of the stir pin and has a front portion and a rear portion opposite to the front portion along the rotation axis. A tip end of the stir pin projects from the front portion. The housing houses the pin holder such that the pin holder is rotatable relatively to the housing. The tip end of the stir pin projects from the housing. The housing includes an engaging portion engageable with a spindle frame of a machining head such that the rear portion of the pin holder is attached to a rotation spindle of the machining head to rotate the pin holder. The rotation spindle is rotatable relatively to the spindle frame.

A production monitoring system has a production monitoring server, a network communication system, production monitoring data store, and production monitoring module. The system is configured to receive, from multiple construction locations, information relating to weld locations, welding parameters, and inspection status for individual welds. Welding information is stored within data stores and is retrieved on request to generate inspection reports containing weld locations, welding parameters, and inspection status for individual welds. Inspection reports can be delivered remotely to a plurality of electronic devices and may contain data from x-ray or ultrasound weld inspections. Weld location may be generated by GPS or by one or more location sensors. The system can receive updated inspection information and update the corresponding information in the data store. Inspection reports can incorporate welding information within a two-dimensional map or three-dimensional model of a construction location.