Square Drive Tapping Screw #10x1 1/2"

Sold in sets of 100 Tapping screws are threaded fasteners that form their own hole and tap their own threads when driven into different materials. They can be used to combine two different types of materials or to screw in areas where access is only one-sided.  They have a wide range of tip and thread patterns, and are available with almost any possible screw head design.  They are often case-hardened to make them hard enough for the intended substrate.