M4-0.7 x 40mm 內六角螺絲 | 圓頭內六角驅動 | 全牙 | 316 不鏽鋼 (300 顆/包)

The hex socket drive bites perfectly with my Allen key, no stripping even when I torqued them into a steel jig. All 300 threads looked clean and uniform, and the 40mm length was exactly what the drawings called for. These are going straight into my permanent tooling builds.

The hex socket drive on these M4 screws gives a really solid grip with my Allen wrench, and the 316 stainless feels more corrosion-resistant than the 304 I've used before. Perfect for rebuilding a jig fixture in my shop.

These replaced some coated ones that had started to pit, and the 316 stainless finish looks far more solid for our damp workshop environment. The button heads sit flush on the jig plates and the hex socket took a lot of torque without stripping.