HOLO-KROME 42047 براغي رأس سداسية مقبس نقطة كوب محززة 3/8-16 × 3/8 بوصة | فولاذ سبائكي أكسيد أسود حراري (100/عبوة)

The hex socket drive is machined cleanly, so the wrench seats deep and doesn't strip even when I’m torquing them down on a shaft. The thermal black oxide finish also gives them a nice even grip right out of the box.

The black oxide finish on these screws gives them a nice, uniform look, and the knurled cup point really bites into the shaft. I used them to secure a pulley on a small motor and they held tight without any slippage. Exactly what I needed for this job.

Installed these set screws yesterday to secure a gear on a keyless shaft, and the knurled cup point really locked it in place without any slipping. The black oxide coating seems durable and should resist rust well.