‘A’ Shape – Shank Diameter 6mm | Suitable for portable die and straight hand grinders. All points are aluminium oxide with ‘rubenite?’ as standard for all general-purpose grinding and deburring on steels and most metals. Shank diameters are metric as listed below with inch sizes available on request. Maximum speeds are quoted assuming that collet to back of point does not exceed 12.7mm (1/2”) and are for guidance only.