The SD120-E brushless electric screwdriver delivers precision process control. The electric screwdriver increases productivity as one tool can be programmed to do the job of multiple conventional tools, saving time, maintenance cost, space and training. The innovative automation fastening system provides the ability to quickly transform the manufacturing area along with the flexibility to make steady product improvements for small or large production batches. The low inertial force provides smooth reaction-less operation with little G force to assembled parts. The failure of a three-cent fastener that isn't properly tightened can lead to catastrophic or latent failures. Fasteners that are insufficiently fastened can vibrate loose and excessive torque can strip threaded fasteners. The power assembly tool provides a consistent repeatable process control and eliminates potential variations.