SEMS Screws

SEMS SCREWS

SEMS Screws are screws pre-assembled with free spinning washers. The assembly typically contains one plain washer and one split spring washer.

The washers are held in place with the major diameter of the thread being larger than the hole of the washer. This is achieved by inserting the washers before thread rolling.

SEMS screws provide design and manufacturing efficiencies by combining multiple parts, captive washer and screw, into one versatile fastener.

This has many benefits which have revolutionised assembly manufacturing processes, particularly in the Aerospace Avionics sector.

Advantages

– Increased productivity by eliminating hand assembly of washers with the screws.
– Permanent assembly ensuring that the washers are not misplaced.
– Safety for the product as there is no chance of a washer being dropped into the assembly.

– One part to inventory, track and assemble.

SEMS screws work well in products with small dimensions, allowing for seamless integration and assembly with a lower risk of error or failure.

Available in a number of head and drive options.

Pan Phillips SEMS Screw

Pan Phillips Screw with assembled Plain Washer & Spring Washer.

Available in Stainless Steel AISI 304 A2.

Ready stock from M1.6 to M6.

Pan Phillips SEMS Screws SS-304 A2 B4B20 – Download Datasheet

SHCS Allen Cap SEMS Screw

SHCS Screw with assembled Plain Washer & Spring Washer

Available in Stainless Steel AISI 304 A2.

Ready stock from M3 to M6.

SHCS Allen Cap SEMS Screws SS-304 A2 B4B51 – Download Datasheet

SEMS – Special Combination with Small OD Plain Washer

We now have a special SEMS screw with a small OD Plain Washer available in stock.

Suitable for many electronic assemblies with smaller space availability.

Available in Stainless Steel AISI 304 A2.

Pan Phillips SEMS Screws with Small OD Washer SS-304 A2 B4B20-1 – Download Datasheet

Hex Head with Phillips SEMS Screw

Hex Screw with assembled Plain Washer & Spring Washer with Phillips drive.

Available in Stainless Steel AISI 304 A2.

Ready stock from M4 to M6.

Hex Phillips SEMS Screws SS-304 A2 B4B17 – Download Datasheet

Other head styles on order.

Application Areas

SEMS can be used anywhere where a screw and washer(s) are required.  Application examples below:

  • Avionic communication systems
  • Flight control systems
  • Electronic engine control systems
  • Electronic warfare and countermeasures
  • Infra-red systems and cameras
  • Missile & ground munition systems
  • Naval & ground fire control systems
  • Display systems
  • Control consoles
  • Battery packs
  • PCB assembly
  • Drone sub assemblies

Key Benefits

  • Reduces Foreign Object Damage (FOD)
  • Reduces component assembly time
  • Reduces inventory count
  • Improves ease and speed of assembly
  • Eliminates downtime due to lost components
  • Lowers kitting part count