Nut pre-tightening device for engineering construction

The invention relates to the field of equipment application of engineering construction, in particular to a nut pre-tightening device for engineering construction. The nut pre-tightening device for engineering construction is easy and convenient to operate and can adapt to different use modes. A nut pre-tightening device for engineering construction comprises a pistol drill, a grip, a connecting and fixing supporting column, a tightening mechanism and a pre-tightening mechanism, the grip is connected to the lower side of the left portion of the pistol drill, and the connecting and fixing supporting column is connected to an output shaft of the pistol drill. A nut is clamped and fixed by a guide clamp through a first spring, then a pistol drill can be controlled to enable the nut to be rotationally screwed into a screw rod to realize pre-tightening, meanwhile, a rotating roller can be rotated, the nut can be placed on the screw rod, then the screw rod can be held by a hand, the nut is in contact with the rotat