Button Head Sems Screw

Description

HBS Fasteners manufactures premium Button Head SEMS Screws, which are machine screws that come with a free-spinning washer (or set of washers) held permanently in place by the rolled threads. The SEMS design (from the German Sems-Schrauben) ensures that the washer cannot fall off, preventing component loss on the assembly line. By combining a low-profile Button Head with integrated locking or flat washers, these screws provide excellent load distribution and surface protection while maintaining a sleek, modern appearance.

Technical Specifications

• Standard: Manufactured in accordance with ISO 7380 (Head dimensions) and DIN 6900 (SEMS standards).

• Washer Types: Available with a variety of pre-assembled washers:

  • Flat Washer: For surface protection and load distribution.

  • Spring/Lock Washer: For high-vibration resistance.

  • Internal/External Tooth Washer: For electrical grounding and anti-rotation.

• Drive Type: Internal Hexagon Socket (Allen) or Torx (Star) drive for precision tightening.

• Size Range: Available from M3 to M12 with various washer combinations.

Material & Quality Excellence

• Stainless Steel: Available in A2 (304) and A4 (316) for superior corrosion resistance.

• Other Materials: Produced in Grade 10.9 and 12.9 High-Tensile Alloy Steel for demanding mechanical applications.

• In-House Control: Utilizing raw materials from our own wire drawing facility, we ensure the thread rolling process is perfectly timed so the washer remains loose enough to spin but cannot be removed. This ensures 100% reliability in automated “pick-and-place” assembly systems.

• Surface Finishing: Options include Zinc Plating, Black Oxide, Nickel Plating, and Trivalent Passivation.

Key Application Areas

• Automotive Electronics: Ideal for securing sensors, ECU housings, and interior modules where vibration is constant.

• Electrical Appliances: Widely used in washing machines, dishwashers, and HVAC units to prevent loosening over time.

• Industrial Automation: Perfect for robotic arms and conveyor systems where losing a small washer inside the machinery could cause a failure.

• Consumer Electronics: Used in computer chassis and power supply units for grounding and secure structural assembly.