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Solutions: Specialty Threaded Nuts & Bolts

WALC™ Washer Anti-Locking Captivation

Perfect for SEMS in Automated Assembly!

The WALC™ solution prevents captivated washers from sliding over the thread like regular SEMS. The WALC feature:

The Washer Locking Problem The Problem Washer Locking occurs when washer slides over thread
The WALC Solution The Solution WALC prevents washer locking by serrating partial thread
  • Maintains tensile strength
  • Retains thread engagement
  • Uses washers of any style and thickness
  • Adds a solution for SEMS at no extra cost

WALC works with applications where washer locking:

  • Jams automated feed systems
  • Interferes with the operator driving the screw
  • Prevents screw from seating properly
  • Causes parts to become unusable

Close-up of WALC SolutionWasher Anti-Locking Captivation makes it impossible for the washer to lock. By serrating the partial thread beneath the screw head (shown left), WALC becomes:

- integral to the screw thread
- extends for one pitch minimum from washer bearing surface


Contact an EFC Sales Engineer to learn about the WALC solution today!