براغي رأس مقبس 2-4-1/2 × 7-1/2 بوصة | محرك مقبس سداسي | خيط جزئي | سبيكة فولاذ أكسيد أسود حراري

I needed a longer fastener for a custom clamping fixture, and the partially threaded shaft on these made alignment much easier than standard bolts. The black oxide finish also slid into the tapped holes without any binding.

These screws fit perfectly into the jig I was building, and the hex socket made tightening them in a tight spot much easier than I expected. The black oxide coating seems durable and should hold up well in my machine setup.

I’ve used these partially threaded screws on a drill jig and the thermal black oxide finish seems tough enough to resist scuffs during assembly. Fit was tight in the hex socket, just as you’d want for precise work. Definitely replacing old mild steel fasteners with these going forward.