HOLO-KROME 86580 براغي رأس مقبس 1/4-20 × 3-3/4 بوصات | محرك مقبس سداسي | فولاذ سبائكي مؤكسد أسود حراريًا (100 / عبوة)

Used a full box assembling a custom machine table and every single screw threaded smoothly without any binding. The black oxide finish looks clean and professional, plus the heads didn’t strip when torqued down with a hex driver.

Had to swap out the old bolts on a fixture at work, and these threaded in smoothly without any binding. The black oxide finish looks really clean and seems like it'll resist rust better than the plain steel ones I've used before.

Installed these in a jig I’m building and the black oxide finish held up great against the clamping force. The threads cut cleanly into pre-tapped holes without binding, and the 3-3/4" length gave me exactly the engagement I needed for a thicker fixture plate.