M6-1 x 30mm 內六角螺絲 | 圓頭內六角驅動 | 全螺紋 | 10.9級合金鋼 熱處理黑氧化 (400顆/包)

Just finished replacing all the cap screws on a jig I use daily — the black oxide finish is holding up way better than the zinc-coated ones I had before. They fit perfectly with no wobble, and the 30mm length was exactly what I needed for my setup.

Installing these on a production fixture was straightforward, and the hex drive seated cleanly without any stripping. The black oxide finish feels durable, and having a full box of 400 means I won't run out mid-project.

Used these on a custom jig for a production run and every single one seated flush without any issue. The black oxide finish held up great against minor coolant splashes. Exactly what I needed for precision tooling work.