براغي رأس أسطوانية HOLO-KROME 77544 1/2-20 × 4-1/2" | محرك سداسي داخلي | فولاذ سبائكي مؤكسد أسود حراريًا (25/عبوة)

The threads are clean and the thermal black oxide finish held up perfectly against the chatter from my lathe; they seated deep into the bore without any galling. I’ve got 22 left in the pack, and they’ll be the go-to for my next tooling fixture.

Used these for a custom jig build and the 4-1/2" length was perfect for a deep clamping setup. The hex drive seated cleanly and the black oxide gives them a nice, uniform look.

Got these for a custom jig I was building, and the thermal black oxide coating has held up great against chips and dust. The hex drive seated perfectly with no wobble. Exactly the right fit for precision work.