Lag screws longer than 12 inches will have a minimum thread length of 50% of the screw length up to a maximum of 8 inches

1 1/2-12 Grade 2 Finished Hex Nut Zinc Plated

1-8 x 6 Grade 8 Hex Cap Screw Yellow Zinc Plated

43/64 x 6 Reduced Shank Drill Bit (1/2 Shank)

the hardness rating is HRC 24-35

1/16 Cobalt Heavy Duty Jobber Drill Bit (12) Flat Washers Silicon Bronze Lag screws longer than 121 16 Cobalt Heavy Duty Jobber Drill Bit . Heavy duty construction made to Type J aircraft specifications. Used for drilling holes in hard, tough materials such as stainless steel, titanium, high temperature and high strength alloys. High red hardness of cobalt permits speeds 30% greater than standard heavy duty split point (HSS) drills.