M33-3.5 x 200mm 內六角螺絲 | 六角驅動 | 部分螺紋 | 等級12.9 合金鋼 熱處理黑色氧化

I needed a fastener that could handle serious torque for a custom press fixture, and the 200mm length plus the Class 12.9 rating made these exactly what I was after. The hex socket drive engaged cleanly with my Allen key, and the black oxide finish has a nice low-glare look.

Installed these in a heavy-duty jig and the hex socket drive held up perfectly under full torque. Class 12.9 strength feels solid—no stripping or deformation during assembly.

The thermal black oxide finish on these screws looks professional and seems to resist wear well in my jig setup. The 200mm length was exactly what I needed for a deep assembly, and the threading pattern held securely without slipping.