AFTE Store - Examination of Consecutively Manufactured Slotted Screwdrivers

This study examined the identification of five consecutively manufactured slotted screwdrivers. Four variables were examined: tool, blade working surface, angle of application, and direction of movement. Control toolmarks (Test vs. Test) were generated, compared, and found to reproduce with significant agreement of individual characteristics (identification). Pushed marks were compared to pulled marks, keeping other variables, such as the tool, working surface, and angle, constant and were also found to reproduce with significant agreement of individual characteristics (identification). However, comparisons between two vertical angles (30+ vs. 60+), blade working surfaces (Side A vs. B), and tools (Tool vs. Tool), exhibited only a random correspondence of striae (misidentification).