M20 X 60mm 平頭內六角止付螺絲 | 合金鋼 (10顆/包)

The hex socket drive made torquing these into a tight spot way easier than wrestling with a wrench. Set them on a pulley shaft last week and they haven't budged a millimeter since.

Finally, a set screw that stays put in high-vibration machinery. The flat point grips the shaft much more securely than the pointed tips I’ve used before, and the hex socket let me torque it down without any rounding.

These set screws are exactly the right size for mounting a heavy-duty jig on my mill table, and the hex socket drive makes cinching them down in tight spots a breeze. The flat point grips securely without marring the surface underneath. Really solid alloy steel for the price.