Carmex Precision Tools’ Quick Change series of toolholders feature polygon shanks for better gripping. According to the company, the polygon taper ensures automatic radial centering and even pressure around the coupling. The 1.4-degree tapered polygon shank is interchangeable with most manufacturers. The toolholders feature internal coolant bores and are available for internal and external threading applications in a range of metric sizes. Both configurations are available for 16-mm (3/8") or 22-mm (1/2") thread turning inserts.