M36-4 X 320mm 內六角螺絲 | 內六角驅動 | 半牙 | Class 12.9 合金鋼熱處理黑色氧化物

Installed these in a jig for a production run, and the thermal black oxide coating held up under heavy use without galling. The 320mm length gave me just enough thread engagement for a secure hold. Exactly what I needed for a high-torque application.

The hex socket drive seated perfectly on my torque wrench without any wobble, and the 320mm length gave me just enough reach for a tight jig setup. Class 12.9 alloy steel feels reassuringly solid for the machining work I’m doing.

Installed these in a jig for a repetitive drilling setup and they've held torque perfectly through hundreds of cycles. The black oxide finish on an M36-4 thread is exactly what I needed for corrosion resistance in a shop environment.