HOLO-KROME 72228 براغي قبعة بمقبس سداسي 1/2-13 × 1-1/4 بوصة | محرك مقبس سداسي | فولاذ سبائكي بأكسيد حراري أسود (50 / عبوة)

Put a fresh set of these on a repair fixture last week, and the black oxide finish slid into tapped holes much smoother than the zinc-plated ones I'd used before. The hex socket drove tight without any cam-out, even on the last few threads.

Installing these in a tight jig frame was a breeze thanks to the hex socket drive, and the thermal black oxide finish seems durable. They seated perfectly with no wobble, making the assembly feel solid and secure.

Used a full pack of these for a custom fixture on our mill, and they all torqued down consistently without any binding. The black oxide finish seems to hold up well against coolant splashes.