A new gage block system for measuring fastener gage protrusion has been developed that is precise and cost effective. A chamfered gage bore and shank constraint inserts provide improved wear characteristics and a ten to one reduction in block requirements. Accuracy and repeatability performance makes the system an attractive candidate for Statistical Process Control for the tightest tolerance fasteners. A new “block custom” calibration process assures accuracy and allows wider tolerances on gage block dimensions. Through better control of gage protrusion in fastener manufacturing, airplane manufacturers can expect improvements in fastener installation quality and eventually in customer satisfaction.