... Material : Carbon steel Finish: Black Zinc Plated Description: Machine screw 5/16x1" Head Dia..69" - .719"Head Height.156" ... 60 employees and almost 40 sets of cold heading machine with rolling thread mchine in our factory . Such ... , tapping .... The annual sales of us is about 3.5 million dollars with 20% export to USA , Norway , ... company like Midea Group , Vanward Group … Machine screw 5/16x1"