M4 X 6mm 杯端內六角止付螺絲 | 合金鋼鍍鋅 (1000入/包)

Used a handful of these to lock a sprocket onto a shaft, and the cup point actually bit in nicely without slipping. The hex socket makes tightening them in a cramped spot much easier. For a thousand pieces, this pack will last me years.

These set screws held my pulley in place perfectly on the first try. The hex socket drive made it easy to tighten in a cramped spot.

The cup point really bites into the shaft, so these set screws hold firm without slipping. I used them to secure a pulley and was impressed that all 1,000 had clean threads and consistent zinc plating.