The plane stress local torsion (PSLT) is an attractive method to strengthen the material in the areas of interest. A closed form solution of the problem is complex and an interpretation of the measured raw torque-twist data into the effective stress and strain is not straightforward. These hinder the optimization and control of the technique. In this study, the PSLT test was performed using Ti-IF steel specimens and their torque-twist response and radial distortion were compared with those obtained from an elastic-plastic model of the PSLT developed by the commercial finite element software, ABAQUS. The resultant microstructure in the samples as a result of large local shear strains and the extent of deformation were studied using SEM and a grid distortion technique, respectively. Mechanical property changes after the PSLT processing were characterized in samples of different geometry using a dedicated formulation based on the similarity theory. The micro shear punch tests allowed characterizing the gradient of the reinforcement in the radial direction of the samples.