M8-1.25 X 340mm 六角凹頭螺絲 | 六角驅動 | 部分螺紋 | 12.9 級合金鋼熱處理黑氧化物 (5 顆/包)

The black oxide finish gives these a solid, professional look, and the hex socket drive seated perfectly with my Allen key without any wobble. Threads are clean and sharp, so they grabbed right away in the jig I'm building.

Finally found the right length to mount a motor mount on my milling machine. The partially threaded shank gives just enough grip without bottoming out in the blind hole. These should hold up under heavy cutting loads.

These 12.9 alloy steel screws are the real deal for heavy-duty jig work—the thermal black oxide finish looks clean and seems tough. The 340mm length was exactly what I needed for a deep fixture assembly, and the hex socket drive made installation straightforward without stripping.