M30-3.5 X 140mm 소켓 캡 나사 | 육각 소켓 드라이브 | 부분 나사산 | 12.9급 합금강 열처리 블랙 옥사이드 (2 / 팩)

Needed some heavy-duty fasteners for a jig build and these M30s handled the torque without any issues. The partially threaded design made alignment much easier than fully threaded bolts.

The thermal black oxide finish looks properly done, no uneven spots or tool marks along the shank. Threads engage smoothly on the first pass even with the M30 size, and the partial threading gave me the clamping length I needed on a steel tooling plate.

Fit perfectly in my jig fixture; the 12.9 alloy steel feels incredibly solid under torque. The black oxide finish on these M30 screws also seems durable, so they should hold up well over time.