When a screw reaches the collar

Yellow zinc plated bolting will meet or exceed ASTM F1941

They are actually stronger than most metal and chemical anchors

3/4-16 x 5 1/2 Grade 8 Hex Cap Screw Yellow Zinc Plated

1/2 x 16 Hex Lag Screw Hot Dipped Galvanized

21/64 Cobalt Heavy Duty Jobber Drill Bit (6) Gutter Screws When a screw reaches the21 64 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.