Torque lock nut

Figure 12.8. Locking nuts (a) standard lock nut (b) slotted and castle nuts (c) Nyloc nut(d) Aerotight nut(e) Philidas self-locking nut (f) torque lock nut...

A fourth type, known as a torque lock nut. Fig. 12.8(f), has the top part of the nut deformed to an elliptical shape which grips the thread as the nut is applied. This ensures close contact between the threads, preventing the nut from working loose. 

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