M4 x 4mm 杯頭內六角止付螺絲 | 合金鋼 (1000個/包)

The cup point bites into the shaft nicely and doesn't walk loose under vibration, even at just 4mm of length. I've used maybe 200 of these so far for jig fixtures and every single one threaded clean. The alloy steel feels plenty hard for the torque I'm putting on them.

I was a bit worried about the hex socket stripping, but the high-torque design held up perfectly when I tightened them into a tight spot on my equipment. The 1000-count pack is great value for the build quality.

The cup point tip on these screws gave me a much cleaner finish on my aluminum brackets compared to the flat-head ones I used before. That hex drive definitely helps you torque them down without stripping, and a full thousand in the pack is plenty for several projects.