In 1988, Aharonov, Albert, and Vaidman presented a theoretical basis for weak-value amplification, a method of pre- and postselecting an ensemble to effectively amplify the observable result of an interaction.  Based on the work of Howell et al. at Rochester, we have developed a device that uses weak-value amplification for measuring angular deflections of torsion balances with a demonstrated sensitivity better than 10 prad/rt-Hz.  I will present a background of weak-value amplification, a brief overview of our group's torsion-balance experiments, and a description of the development, capabilities, and future application of our "interferometric quasi-autocollimator".