Screw Withdrawal Resistance in Near-Edge Applications
Practical application of long self-tapping screws (STS) in near-edge applications sometimes
requires pre-drilling a pilot hole. It is commonly assumed that pre-drilling of a pilot hole with a diameter equal to the minor fastener diameter has no impact on withdrawal resistance. Designers have also assumed that, due to the lack of prescriptive code guidelines, pre-drilling guidelines established for lag screws can be applied to STS and smaller end and edge distances can therefore be used. The question of whether or not this pre-drilling impacts the fastener withdrawal resistances in near-edge applications is addressed in this newsletter.