1/2-13 X 4" 內六角螺絲 | 內六角驅動 | 尼龍防鬆塗層 | 部分螺紋 | 合金鋼黑氧處理 (25 / 包)

The black oxide finish looks sharp in my tool drawer, and the nylon patch keeps these threaded bolts from backing out on my milling fixture. Threads cut clean into 1018 steel with no galling, and all 25 in the pack came sized right.

The black oxide finish on these gave them a nice, uniform look right out of the package, and they threaded smoothly into my jig fixture without any binding. For a 1/2-13 screw this size, the socket drive gave me plenty of leverage with just a hex key.

Finally, a bolt that doesn't strip the hex socket on me — the black oxide finish feels tough and the nylon patch holds tight against vibration. Used them to secure a jig on my milling table and they seated perfectly without any wobble. Exactly what I needed for heavy-duty tooling work.