M6-1 X 40mm 內六角螺絲 | 六角孔驅動 | 半牙 | 8.8級合金鋼 熱處理黑色氧化 (400/包)

Pulled these out for a precision assembly this morning and the partially threaded design made alignment noticeably easier. The black oxide finish feels more durable than the zinc-coated ones I've used before.

The partial threading on these M6-1 x 40mm screws makes positioning in jigs way easier, and the black oxide finish gives them a clean, professional look right out of the box. Threads are crisp and the hex socket engages perfectly with my driver. For a bulk pack of 400, the consistency in length and

Finally, a set of M6-1 screws that actually hold up under torque—the hex socket drive didn’t strip on me even after multiple tightenings. I used them for a jig build and the partial thread gave just the right grip depth.