HOLO-KROME 72138 براغي رأس مقبس 5/16-18 X 2-1/4" | محرك مقبس سداسي | سبيكة فولاذ مؤكسد أسود حراري (100 / عبوة)

I was glad to find these in the correct 5/16-18 size for my jig build. The black oxide finish has held up well against minor scrapes during assembly.

The thermal black oxide finish is exactly what I wanted for my tooling setup—it's even and doesn't flake off during assembly. Threads cut smoothly into the steel plate, and the hex socket seated the screw firmly without any wobble. Kept a few extras in my drawer for the next jig project.

Used these on a metal jig I’m building, and the black oxide finish makes them look clean and resist rust nicely. The hex socket drive seated perfectly with my driver, no stripping at all.