Abstract: The tapered fastener system is one of the more reliable fastener systems for assuring the longevity of connected members, especially like those found in aircraft, which are subjected to stresses on the order of 20,000 psi and up. However, in order to achieve such joint longevity, a high quality installation of the tapered fastener has been determined to be necessary. The three areas which are the most critical to such an installation are: hole finish, fastener-to-hole bearing contact, and interference fit of fastener in hole.The apparatus herein proposed evaluates these three factors to determine if the necessary quality level has been attained in the fabrication of the fastener and in hole preparation prior to actual installation. To this end this apparatus includes a probe and receptacle, simulating the fastener and hole respectively in conjunction with a computer and display box to electronically and instantaneously determine hole condition and comparative fastener-to-hole bearing and interference.