HOLO-KROME 73074 1/4-28 × 2-1/4" براغي رأس مقبس | محرك مقبس سداسي | سبائك فولاذية بأكسيد حراري أسود (100 / عبوة)

The black oxide finish on these screws is holding up well against oil and chips in my jig setup, and the hex socket drives cleanly without stripping. They fit perfectly in my precision fixture plate threads.

Just replaced the cheap bolts on my milling vise with these, and the black oxide coating fits into the slots perfectly without binding. They thread in smoothly with no wobble, and the hex socket grabs the Allen key tightly.

I was worried about stripping the hex drive, but these threads are cleanly cut and the black oxide finish looks professional. They seated smoothly into my jig setup without any binding.