براغي رأس سداسية M3-0.5 × 20 مم | محرك سداسي | خيط كامل | فولاذ سبائكي درجة 12.9 مؤكسد أسود حراريًا (600 / عبوة)

The black oxide finish on these M3 screws held up perfectly during assembly, no galling at all. Fit tighter than standard stainless ones in my jig fixture. Exactly what I needed for precise adjustments.

I needed these for a precision tooling fixture and was impressed how consistently tight the hex socket drive engages. The thermal black oxide finish is surprisingly uniform across all 600 pieces, no duds in the batch.

Used these for jig assembly and the 12.9 alloy steel feels noticeably tougher than standard screws I've tried. The black oxide coating holds up well against minor scuffs during installation.