Lock nuts are very useful and are used by engineers and mechanics. Washers are placed on either side of the wheel and a lock nut is finally threaded in position. This is a highly effective method of securing wheels on shafts / axles. As the nut is tightened, the thread on the shaft / axle cuts into the nylon, holding it firmly in position. As the wheel rotates a normal nut will loosen because of friction and vibration of the wheel. However, the nylon holds the nut firmly in position. At Quickco we stock locking nuts, bumper locking nuts, screw grommets, headlight locking nuts and more.