براغي رأس مقبس #4-40 × 3 بوصة | محرك مقبس سداسي | ملولبة بالكامل | فولاذ سبائكي أكسيد أسود حراري (100/عبوة)

I needed some longer fasteners for a jig I was building, and these #4-40 x 3" socket cap screws fit perfectly. The hex socket drive made them easy to tighten without stripping, and the black oxide seems durable.

Finally got the #4-40s in a 3-inch length for mounting some circuit boards in a tight enclosure. The hex socket drive makes it easy to get good torque even in deep holes. These feel sturdy and the black oxide finish looks clean.

Needed some longer 4-40s for a custom jig, and these thermal black oxide screws fit perfectly into the precision assembly. The threads are clean and the hex socket drove smoothly without any cam-out, even at three inches long. A solid pack for the price.