HOLO-KROME 73145 1/2-20 X 3-1/2" 內六角螺絲 | 內六角驅動 | 合金鋼熱處理黑氧化 (25 顆/包)

Used these to secure a heavy steel fixture on a custom tooling frame, and the black oxide finish held up perfectly under repeated tightening. The hexagonal socket drive gave a solid grip without any cam-out issues, which saved me a lot of frustration. Exactly what I needed for precise assembly work.

I was building a jig for a repeat drilling operation and the black oxide finish on these screws gave them just enough grip to hold torque without galling the threads. The socket drive bit fit snugly right out of the box, no wobble.

These cap screws seated perfectly in a jig I'm building for a production run, and the hex drive bit fit snugly without any wobble. The alloy steel feels dense and well-machined, and all 25 pieces had clean threads right out of the package.