M4-0.7 X 40mm 內六角螺絲 | 六角驅動 | 部分螺紋 | 8.8級合金鋼 鍍鋅 (400 / 包)

Installing these on a custom tooling fixture went smoothly thanks to the fully threaded shank allowing precise depth adjustment. The hex drive held up perfectly under repeated torque without any stripping or cam-out.

Used these for securing a jig on my drill press and the socket drive made tightening easy even in tight spots. Class 8.8 alloy steel feels solid, no deformation at all.

I was worried about rust on these M4 screws, but the zinc plating seems tough and even after a few days in my damp workshop, no corrosion. They thread easily into my jig fixtures with a standard hex key.