M6-1 x 40mm 六角穴付きボルト（ソケットキャップスクリュー） | なべ頭六角穴付き | 全ねじ | 10.9級 合金鋼 黒色酸化処理 (400本/袋)

The black oxide finish on these M6-1 x 40mm screws gives them a nice, non-reflective look that handles oil and grime without showing fingerprints. I’ve been using them to lock down a few precision fixtures and the hex socket drive hasn’t stripped once, even after torquing them repeatedly. They’re a

These screws bit perfectly into my jig's threaded holes without any binding. The black oxide finish seems durable and the hex drive held the Allen key firmly.

Was pleasantly surprised by how cleanly these threads cut into a steel jig I'm building—the hex drive seated perfectly without any wobble. For under 50 cents a bolt, the Class 10.9 strength gives me real confidence in high-torque applications.