Material, surface finish:
Screw in stainless steel, natural finish.
Ball in stainless steel, natural finish, Delrin or ceramic Si3N4.
Note:
Ball pressure screws, without head, with full ball are used when a clean, polished pressure surface is required. Longer models have been designed especially so that ball pressure screws can be glued up. They allow mechanical connecting elements with external threads to be made cost-effectively for small and medium-sized runs. Silicon nitride (Si3N4) is especially suitable thanks to the combination of its excellent properties. These include great toughness and strength, excellent wear characteristics and good chemical resistance.