SINODRILLS Anchor nuts Anchor nut is used to lock the anchor system, make sure the anchor string is fastened with anchoring site, there usually have hexagonal and spherical two designs. Hex Nut: R25, R32, R38, R51, T76 Spherical nut: R32, R38, T30, T40, T52, T73, T76, T103, T111, T127, T130 etc.