TAPPING SCREW

摘要

The present invention is directed to provide a tapping screw for a soft material having a sufficiently large stripping torque compared to a driving torque and an increased tolerance of a fastening torque, and characterized in that it has threads each having a leading flank and a following flank, the leading flank being designed to be steeper than the following flank, that an R is imparted to a crest of each thread on the following flank side, that an R is also imparted to each flank at a portion contiguous to a root thereof and that the former R and the latter R being designed to connect smoothly to each other at the root.