براغي ذات رأس أسطواني سداسي مسطح | 5/16-18 × 1-3/4" | حبيبات نايلون | محززة بالكامل | سبيكة فولاذ معالجة حرارياً وأكسيد أسود (100/عبوة)

The black oxide finish on these is spot on—it’s even and dark, so they’ll hold up well on my jigs without rust worries. The nylon pellet locks them tight, and I’ve had zero backing out after a couple of hours of vibration. Just wish the packaging gave a clearer count, but the threads cut clean and t

I needed a solid fastener for a custom jig, and the nylon pellet on these screws locks tight without backing out. The thermal black oxide finish looks durable and slid into the pre-tapped holes perfectly.

The hex socket drive made installation much easier than using standard hex screws — no stripping issues. They held tight in my tooling fixture without any wobble, and the black oxide finish looks great.