GN 6303.1 Quick Release Knurled Nuts Steel, with Tapped Through Bore. GN 6303.1 quick release knurled nuts are used in such applications where the nut has to be completely removed after the releasing operation and mounted again rapidly for re-clamping. The nut is tilted over the threaded spindle. When in position, the nut is brought into a straight position for mating of the two threads on the nut and spindle. The nut will then have to be turned only by a fraction of a rotation to achieve clamping.