Portable calibration system

A power tool torque calibration system, comprising:

• a portable shippable container configured to house a mechanical tool interface, a user interface and central processor unit;
• the mechanical interface including a reaction collar coupling and a square spindle coupling jointly mounted to simultaneously couple with a high torque power tool to be calibrated and configured such that the mechanical interface simultaneously locks the power tool against spinning relative to an axis of rotation of an output spindle of the power tool and receives torque output from an output spindle of the power tool;
• the mechanical interface further comprising a torque transducer operatively connected to the central processor, the torque transducer including a cascading set of load cells integrally formed with the square spindle coupling;
• the central processor unit configured to process signals received from the torque transducer and calculate and upload to the power tool being calibrated a calibration correction factor specific to the power tool being calibrated;
• and
• the calibration system configured to automatically conduct the calibration of a high torque power tool using only power from a self-contained battery system in the calibration system and without the use of an external power supply.