براغي رأس مقبس M36-4 × 240 مم | محرك مقبس سداسي | ملولبة جزئياً | سبيكة فولاذ من الفئة 12.9 مؤكسد أسود حراري

Finally got these installed on a heavy jig I’m building, and the thermal black oxide finish feels durable and prevents rust out of the box. The hex socket drive made tightening them in tight spots much easier than a standard hex head.

Installed these in a large jig frame and the 12.9 alloy steel handled the torque without any signs of stress. The black oxide finish seems like it’ll resist shop grime well.

Class 12.9 is no joke—these bolts took some serious torque without stripping the hex socket. The black oxide finish feels slick and even, but the partial threading could've been a bit longer for my setup. Solid choice for heavy jig work though.