Stainless Steel-Hexagon head screws GN 933.5 with brass or plastic pivots are used when pressure dents or damage to the clamping surface must be avoided.
Stainless Steel-Hexagon head screws GN 933.5, type ZK, feature a spherical pivot whose diameter d4 is smaller than the core diameter d1 of the thread. This makes them suitable for holding thrust pads GN 631 / GN 631.5 which must be ordered separately.