7/8-9 X 3-1/2" 內六角螺絲 | 六角插座驅動 | 美國製造 | 合金鋼 熱處理黑色氧化（每包10顆）

The black oxide finish on these screws is exactly what I needed for a jig build—it resists rust better than zinc-plated stuff I’ve used before. Hex drive seats cleanly without stripping, even in tight spots. Solid quality for precision assemblies.

I needed some heavy-duty fasteners for a jig I was building, and these black oxide screws fit the bill perfectly—the threads cut cleanly into the alloy steel without any galling. They’re solid and feel much more robust than the import stuff I’ve used before.

I’ve been using these for jig repairs and they fit perfectly without any wobble—the hex drive really grabs the Allen wrench securely. The alloy steel feels dense and tough, definitely built to last.