5/16-24 x 2-1/4" 內六角螺絲 | 六角驅動 | 美國製造 | 合金鋼熱處理黑色氧化 (500 / 包裝)

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.