A tension-testing machine is described for determining the mechanical properties of thin-foil specimens with dimensions scaled so that the width-to-thickness ratio is sufficiently small so that the strain across the specimen is uniform. The loads are applied by means of a computer-controlled stepping motor having a linear motion of 10 nm/step. The gage-length change is measured optically. There is the capability to vary the strain rate between 4 × 10⁻⁴/s and 8/s and for low-frequency fatigue testing. The mechanical properties of electroplated nickel, Ni-Mo, and Ni-P alloys were determined.