HOLO-KROME 60086 5/16-18 x 1-3/4" 內六角圓頭螺絲 | 平頭內六角驅動 | 合金鋼熱處理黑色氧化 (100 / 包)

The black oxide finish on these screws held up perfectly during assembly, no galling or binding at all. I used them for a jig build and they seated flush with the flat head just like I needed.

The threads bit cleanly into my fixture plate without any galling, and the flat head sat flush on the first try. I've got a box of these for jig work now, and the thermal black oxide has held up through a couple of oily shop days so far.

The black oxide finish on these screws is holding up well against scuffs in my jig setup, and the flat head sits perfectly flush. They threaded smoothly into pre-tapped holes without any binding.