براغي رأس أسطوانية M8-1.25 × 170 مم | محرك سداسي | ملولبة جزئيًا | فولاذ سبائكي من الفئة 12.9 مع أكسيد أسود حراري (50 / عبوة)

I needed a bolt that would hold up under heavy clamping loads, and these 12.9 alloy steel screws haven't budged a millimeter. The black oxide finish is a nice touch too, seems to resist shop grime better than plain steel.

The 170mm length was spot on for the jig assembly I’m building, and the black oxide finish actually looks cleaner than I expected once torqued down. Threads caught smoothly and the 12.9 hardness gives me confidence these won’t strip under load.

Installed these on a heavy-duty workbench clamp and the 12.9 alloy steel held up perfectly under torque. The partially threaded design made alignment easy through thicker sections.