M4 M5 M6 Hexagon Socket Head Cap Screws With Lock Washer And Plain Washer Metal Sems Screw Din912

These SEMS screws feature a hexagon socket head cap (DIN912) combined with both a spring lock washer and a plain flat washer pre‑assembled. The spring washer sits above the flat washer to provide vibration resistance while the flat washer protects the workpiece surface. Made from carbon steel (8.8/10.9/12.9) or stainless steel (A2/A4) with finishes such as zinc plating, black oxide or plain. Sizes M4, M5 and M6 are the most common for precision machinery, moulds and electronic equipment. The socket head allows high torque transmission and is suitable for countersunk or recessed holes.

• CNC machine tools: tool magazines, way covers, rail clamps.
• Industrial robots: reducer housings and motor mounts – double washers prevent loosening.
• Optical measuring instruments: fine adjustment bases.
• Electric scooters and bicycles: battery boxes, controllers.
• 3D printers: hotbed and extruder assemblies.

• Double washer combination – flat washer reduces surface stress, spring washer provides anti‑loosening.
• Hex socket drive – deep engagement, high torque capability, ideal for countersunk holes.
• DIN912 standard – globally recognised dimensions.
• Small diameters (M4‑M6) cover precision to light industrial use.
• Optional nickel or Dacromet finishes for extra corrosion protection.