Nook precision locknuts

Nook precision locknuts are designed to provide adjustment, preload and secure bearings or machine components to shafts and other rotating machine elements. These locknuts allow accurate setting of preload on bearings and are capable of supporting axial loads with very high rigidity without loosening. They also provide very high load carrying capacities by continuous contact of the thread flanks around the circumference.

All Nook locknuts provide locking and loosening prevention within the part itself without the need of additional components, keys or extra machining. The prevention against loosening is accomplished in several ways, depending on the locknut series.

For series MF, MR, TMF and SFZ, locking is accomplished by using brass radial inserts, loaded and secured by setscrews. Series MF, MR and TMF have ground threads and very low axial run-out of 0.002 mm (.00008). SeriesSFZ have machined threads with axial run-out contained within 0.005 mm (.0002).

For series MKR, locking is accomplished by axially shifting a portion of the threads. The design provides increased loosening prevention due to its large contact area. Series MKR have machined threads with axial run-out contained within 0.005 mm (.0002).

Every Nook locknut is manufactured with very low axial run-out. This enables accurate assembly and uniform loading of bearings and other components. The quality of the threaded contacts provide consistent loading even in repetitive assembly (tightening) and disassembly (loosening).

In order to maximize the load-ability of the locknuts the mating thread must be of suitable quality and strength. The dimension tables show static load ratings (C_a) and loosening torque based upon thread quality class ISO 6g or better (4h for high precision applications, such as spindles should be used) and material strength of 690 N/mm² (100,000 PSI). The geometrical tolerances should also be verified. The surface finish of the components (i.e. thread flanks) should not exceed 0.8 µm Ra (32 µinch).