HOLO-KROME 61026 1/4-28 X 1-1/4" 소켓 캡 나사 | 플랫 헤드 육각 소켓 드라이브 | 합금강 열처리 블랙 옥사이드 (100개/팩)

The threads on these are clean and cut perfectly, every single screw seated flush in my jig without any binding. For a hundred-piece box, the thermal black oxide coating came out uniform across the batch, which is exactly what I need for a professional finish.

The black oxide finish is holding up well in my precision tooling setup, no rust after several weeks of use. These screws fit perfectly into the 1/4-28 threaded holes on my drill jig, saving me time compared to the cheaper zinc-plated ones I tried before.

I needed these for a jig assembly, and the thermal black oxide finish adds a nice grip while preventing rust. The flat head sits flush just as expected, making alignment much simpler than with standard hex heads.