براغي ذات رأس مقبس مسطحة 1/2-20 × 4-1/2" | محرك مقبس سداسي | خيط جزئي | فولاذ سبائكي مع أكسيد أسود حراري (25/عبوة)

I needed some heavy-duty screws for a jig I was building, and these black oxide ones held up perfectly under constant tightening. The hex socket drive made installation much easier than a traditional slot, and the partially threaded design was just right for the clamping force I needed.

The flat head sits perfectly flush on my machining fixture, and the black oxide finish looks clean. These replaced some rusted regular hex bolts and the hex socket drive made installation so much easier.

Installed these in a jig for a drilling fixture and the black oxide finish on the threads made seating them smooth without any galling. The hex socket drive held up well under my torque wrench without stripping.