M2.5-0.45×18mm ソケットキャップスクリュー | 六角穴付き | 全ねじ | 12.9級 合金鋼 熱処理黒色酸化被膜 (600本/パック)

The black oxide finish looks properly done, no uneven blotches, and the threads on every screw I've checked are clean. They sit flush in my 3D-printed fixture holes with zero wobble, solid enough for the 12.9 rating.

I needed precise fasteners for a jig I was building, and these 18mm socket cap screws threaded in smoothly with zero wobble. The hex socket drive grabs my driver perfectly every time, and for the price you get a solid 600 pieces that feel tougher than the usual hardware store stuff.

The black oxide finish makes them easy to grip even with oily fingers, and the threads cut cleanly into aluminum without any binding. For the price per piece, I can finally stop scavenging loose screws from old projects.