HOLO-KROME 77500 براغي رأس أسطواني بمقبس سداسي مقاس 3/8-24 × 3-1/2 بوصة | محرك سداسي | فولاذ سبائكي، أكسيد أسود حراري (50 / عبوة)

Replaced the old bolts on my mill’s clamping kit with these, and the black oxide coating is holding up well against cutting fluid. The hex drive fits perfectly with standard Allen keys, no stripping.

The black oxide finish looks superb on my tooling setup, and the alloy steel feels rock-solid when torqued down. Threads ran clean into the fixture without any galling, so these 50 pieces will last me a long while.

Installing these on a jig assembly, the hex socket drive gripped the bit nicely without stripping. The black oxide finish makes them look clean and professional, and for the price you get a solid 50-pack.