HOLO-KROME 08096 1/2" x 4-1/2" 內六角肩螺絲 | 內六角頭 | 內六角驅動 | 合金鋼熱處理黑色氧化 (10 / 包)

The hex drive engaged smoothly without any wobble, and the thermal black oxide finish looks clean and professional. I used one as a bearing surface for a small jig, and it's held up perfectly under repeated use.

The ground shoulder on these is dead-on—I measured it and it’s within half a thousandth. The black oxide finish feels tough and the hex drive bit seated cleanly. Solid hardware for any pivot or axle job.

Needed a replacement axle for a small jig I built, and these precision-ground shoulders fit the bearings perfectly. The black oxide finish holds up well against light rust, though I wish they came in a larger pack for the price.