The quality of threads in nails with deformed shanks influences the resistance of the nail to withdrawal from wood. Thread quality in helically threaded, 4-flute nails is a function of the thread angle and the thread crest pressout, which is the difference between the wire diameter and thread crest diameter. Current market practices for threaded nails contain no reference to thread quality. From thread angle and thread pressout measurements of 25 replicate samples from 258 different 11- and 11-1/2-guage helically treaded nails, the level of variation in thread quality was measured. Significant variation in thread quality was observed, representing three distinct quality levels and more than 100 percent difference in estimated average withdrawal resistance.