HOLO-KROME 72020 مسامير رأس مقبس #4-40 × 3/8" | محرك مقبس سداسي | سبائك فولاذ أكسيد أسود حراري (100/عبوة)

The hex drive on these #4-40 screws fits perfectly into my tooling jigs, and the alloy steel feels incredibly sturdy for such a small fastener.

These are exactly what I needed for a small jig I was building; the #4-40 threads cut cleanly into the tapped holes. The hex socket drive made tightening them down in a tight spot much easier than a standard slotted screw would have been.

The black oxide finish on these screws gives them a nice, uniform look that’s held up well in my tooling setup. I did have to chase a couple of them with a tap to clean the threads, but for a hundred pieces at this price, that’s a minor trade-off.