On the above-mentioned NYLSTOP nuts temperature 120°C -included in the range of diameters between 3 and 8 mm one can assemble a Nylon cap which assures the self-locking action, the sealing t the tread level (test pressure 5 Kg/cm2) as well as the protection of the top of the screw and everything around.
For further details, have reference to the corresponding dimensional sheet.
Contact Howmet for the diameter/type in manufacturing.