1/4-28 X 3/8" 內六角螺絲 | 六角驅動 | 尼龍防鬆 | 全螺紋 | 合金鋼 熱處理黑氧化物 (100個/包)

Finally, a fastener that holds its torque on my jig without stripping—that nylon pellet keeps things snug even after repeat adjustments. The black oxide finish also feels slick and settled into the machine nicely, no residue on my fingers. These are going straight into my precision assembly kit for

The nylon pellet locking feature is exactly what I needed for a jig that kept vibrating loose—these hold firm without any thread locker mess. All 100 came out of the bag with a consistent finish and no burrs, and the 3/8" length sat perfectly flush in my fixture.

The black oxide finish is a nice touch—they look clean and uniform straight out of the bag, and the hex socket drive seated perfectly in my allen key. I’ve been using them to hold a jig together under constant vibration and not one has loosened up on me yet. Solid little screws for the price.