براغي رأس أسطوانية 1/2-13 × 5-1/2" | محرك سداسي | حبيبة نايلون | ملولبة جزئيًا | فولاذ سبائكي مؤكسد حراري أسود (25 / عبوة)

The nylon pellet locking mechanism is a nice touch—these screws stayed put on my milling fixture through a full day of vibration without backing off a thread. The thermal black oxide coating looks clean and uniform across all 25 pieces.

The black oxide finish on these socket cap screws is holding up well in my jig setup, no rust issues after a few weeks. They thread cleanly into tapped holes and the hex drive makes tightening them a breeze.

The nylon pellet on these 1/2-13 socket cap screws locked in tight on my jig build, and the black oxide finish wiped clean easily after cutting fluid drips. Used them to secure a heavy-duty fixture plate, and not a single one loosened under vibration.