براغي رأس سداسية مقاس 5/16-24 × 2-1/4 بوصات | محرك سداسي | صناعة أمريكية | فولاذ سبائكي بأكسيد حراري أسود (500 / عبوة)

Used a full bag of these on a jig fixture and every drive socket was clean and uniform, no stripped heads. The black oxide finish held up well against coolant spray during a week of milling.

I needed a batch of hex drive screws for a fixture build, and these black oxide ones have held up perfectly under repeated torque without any stripping. The 2-1/4" length was just right for the thick clamping plates I was assembling, and every single piece in the package had consistent, clean thread

These screws have a nice, clean thread cut and the black oxide finish feels durable. They seated perfectly into my jig without any binding or galling. Exactly what I needed for a tight-tolerance fixture.