براغي ذات رأس مقبس 1/2-13 × 4-1/2 بوصة | محرك سداسي المقبس | صناعة أمريكية | فولاذ سبائكي مع أكسيد أسود حراري (200 / عبوة)

Installed these on a heavy-duty jig I'm building; the black oxide finish held up perfectly against the wrench, no marring. The threads cut cleanly into the pre-tapped hole, and the full 4-1/2" length gave me just the grip I needed for a solid fixture.

The hex socket drive seated perfectly with my Allen wrench, and the black oxide finish has held up through a week of heavy jig use without any wear. These are solidly machined and the threads ran clean on every one of the two hundred pieces.

I’ve been using these screws for a machine tool fixture and the hex socket drive makes tightening them in tight spots much easier. The black oxide finish seems tough and hasn’t chipped at all during install.