براغي رأس أسطواني M20-2.5 X 260mm | محرك سداسي | ملولب جزئيًا | فئة 12.9 سبيكة فولاذية أكسيد أسود حراري (5 / عبوة)

I needed high-strength screws for a heavy tooling fixture, and the Class 12.9 hardened alloy steel on these is exactly what I was hoping for. The black oxide finish also held up well during assembly without any galling.

Installed these in a jig for a production run, and the 12.9 alloy steel held up perfectly under heavy loads without any deformation. The partially threaded design gave me exactly the clamping length I needed for the assembly.

The hex drive on these M20 screws grabbed the wrench perfectly without slipping, and the black oxide finish feels tough enough for my jig setup. They’re exactly the length I needed for a heavy-duty assembly, and the partial threading made alignment much easier than fully threaded bolts.