Unique 4-corner thread form with raised-ridge technology greatly reduces driving torque

7 x 2 1/4 Simpson Trim-Head Self-Drilling Siding Screw - Square Drive 410 SS - Carton (1000)

53/64 x 6 Reduced Shank Drill Bit (1/2 Shank)

#35 Heavy Duty Drill Bit - Stubby Length

31/64 x 12 High Speed Aircraft Bit Cobalt (3) 2 1/2-4 Socket Cap Screws Alloy Unique 4-corner thread form with31 64 x 12 High Speed Aircraft Bit Cobalt . Manufactured to NAS 907 Type J specifications Heavy duty construction for portable or machine drilling For use in drilling in high tensile strength alloy steels, stainless steels, titanium and other difficult to machine materials Made in the USA