براغي رأس مقبس M12-1.75 × 75 مم | محرك سداسي المقبس | ملولبة جزئيًا | درجة 8.8 من سبائك الفولاذ أكسيد أسود حراري (50/عبوة)

Installed these on a custom jig and the hex socket drive seated perfectly with no stripping. The black oxide finish looks great and seems like it'll hold up well against shop grime.

Used a dozen of these on a heavy-duty tooling fixture and the black oxide finish held up great, no galling on the hex socket drive. The partial threading gave just enough grip without wasting fastener length.

I've been using these in a couple of jigs and they're holding up well under repeated tightening—the black oxide finish looks clean and hasn't shown any wear. The partial threading made alignment a lot easier than fully threaded bolts.