M22-2.5 x 340mm 內六角螺絲 | 六角驅動 | 部分螺紋 | 12.9級合金鋼熱處理黑色氧化

I usually buy 316 stainless for outdoor tooling, but these black oxide ones hold up better in the oily fixtures I use, and the hex drive made torquing them down much easier than I expected.

Threading these into a jig fixture was smooth—the black oxide finish has a nice, grippy texture. I’m using a set for a heavy press frame and the 12.9 alloy steel feels incredibly rigid under load.

The 12.9 alloy steel is no joke—I torqued these into a jig frame and the threads cut clean without a hint of galling. The black oxide finish gave them a nice, uniform grip in the socket, and at 340mm they’re solid for heavy fixtures.