SEMS Screws

Washers are often used in combination with screws to improve the structural integrity of an assembly. Typically, they are separate components. However pre-assembled screws and washers – the SEMS screw, have simplified and improved efficiencies in many manufacturing processes.

What is a SEMS Screw?
A SEMS Screw is a generic term used to describe a screw pre-assembled with a free-spinning lock washer. It is a permanent assembly with the washer held in place by the major diameter of the screw thread being larger than the hole of the washer. The SEMS screw is simple, easy to use and available in many different styles making it well suited for many applications.

Advantages of the SEMS Screw:

  • Low cost and widely available
  • Increases productivity by eliminating hand assembly of individual components
  • Permanent assembly assures that the washer is not dropped, lost or forgotten
  • Ease of use with hand drivers and in automated production programs
  • Available in most screw and washer combinations

Key Considerations When Choosing SEMS Screws:

  • Select the correct configuration for the specific task at hand
  • Good design ensures savings in the long run
  • Proper finishes perform optimally and are aesthetically pleasing
  • Ease of use, particularly in difficult spaces

 

SEMS Screws In Stock at Aspen Fasteners:

 

External Tooth SEMS

Example of an external tooth lock washer sems screw

  • Generates and maintains tension
  • Absorbs torque and prevents slipping
  • Opposes loosening rotation of the screw
  • Absorbs shock and vibration
  • Ideal for larger head screws (round, pan, binding, etc.)
  • When exposed/visible teeth are not a concern
  • Maximizes torsional resistance due to larger radius

 

Internal Tooth SEMS

Example of an internal tooth lock washer SEMS screw

  • Generates and maintains tension
  • Absorbs torque and prevents slipping
  • Opposes loosening rotation of the screw
  • Absorbs shock and vibration
  • Ideal for smaller screw heads (such as fillister heads)
  • Where teeth need to be hidden for function and/or aesthetics
  • Reduces snagging or scratching

 

 

Split Lock Washer Sems

Example of a split lock washer SEMS screw

  • Generates and maintains tension
  • Absorbs torque and prevents slipping
  • Opposes loosening rotation of the screw
  • Absorbs shock and vibration
  • Preferred for use with hardened bearing surfaces

 

Square Cone® Washer Sems

Example of a square cone® lock washer SEMS screw

  • Higher retained clamp load
  • Improved compensation for thermal cycling and vibration
  • Maintains spring action and generates constant load even under high tension
  • Enhances flexibility in component design
  • Ideal for clamping fragile materials and preventing stress cracking around clearance holes
  • Ideal for large clearance holes

24 Hour Delivery Door-To-Door Service With UPS

Aspen Fasteners stocks full lines of SEMS screws in steel. stainless steel and metric  in addition to most other screws, nuts, bolts and washers. Available for same day shipping from distribution centers across the USA. And remember, it’s always free shipping. Expedited next day delivery is also available for those rush requirements.

For more detailed information on SEMS screws click here.

If you don’t see what you are looking for, please contact us and we’ll be happy to help you find what you need.

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