HHIP 1-1/4 X 3/4 X 1-1/8 X 1/2″ 3/8-16NC Knurled Knob Thumb Nut ~ Ideal for adjusting collars, lock nut rings & bearings. ~ Black oxide. HHIP 1-1/4 X 3/4 X 1-1/8 X 1/2″ 3/8-16NC Knurled Knob Thumb Nut Ideal for adjusting collars, lock nut rings & bearings. Black oxide.