M4-0.7 X 16mm ソケットキャップスクリュー | ボタンヘッド六角ソケットドライブ | 全ねじ | クラス12.9合金鋼熱処理黒色酸化被膜 (600個/パック)

The hex socket drive bit into the head cleanly without stripping, and the 12.9 alloy steel feels significantly more rigid than the standard stainless I usually buy for jig work. For six hundred pieces at this price and quality, it’s hard to beat for precision assemblies.

The black oxide finish gives these a clean, professional look that resists fingerprints nicely, and the hex drive grips perfectly with a standard Allen key. I've used about half the box on precision assemblies and haven't had a single stripped head or burr. For the price per piece, the 12.9 alloy st

Used a handful of these for a custom tooling fixture, and the 12.9 grade steel feels noticeably tougher than the usual hardware store stuff. The black oxide finish looks clean and hasn’t shown any wear after a few assembly cycles.