Vlier NNS55AN Threaded Spring Plunger 1/4-28 Steel Locking

Product Description

The VLIER NNS55AN is a threaded spring plunger designed for precise, repeatable positioning and indexing applications in mechanical assemblies. The plunger features a 1/4-28 thread with a 1-inch thread length and a standard plunger projection of 3/16 inches. The Delrin nose provides low-friction contact with minimal surface marring, while the steel body delivers structural durability under cyclic loading. An integrated locking element secures the plunger in the threaded bore to prevent back-out from vibration. Initial end force is 1 pound, with a final end force of 4 pounds, making this unit appropriate for light-duty detent and positioning tasks in tooling, fixtures, and precision equipment.

This spring plunger is suited for installation in machine tool fixtures, assembly jigs, stamping dies, and precision industrial equipment where consistent spring force and positive thread retention are required. The 1/4-28 fine thread is commonly found in tooling plates and fixture components across manufacturing and industrial maintenance environments. The compact body length of 1 inch allows installation in relatively shallow bored housings.

Key Features

• 1/4-28 fine thread with 1-inch thread length for secure engagement in standard tooling plate threads
• Locking element prevents plunger back-out under vibration and repeated cycling
• Delrin nose minimizes surface damage on contact targets
• Steel body construction for durability in industrial environments
• 1 pound initial end force and 4 pound final end force for light-duty detent applications
• Standard plunger projection of 3/16 inches with plunger diameter range of 0.116 to 0.118 inches

Compatibility

Designed as an OEM-style replacement or direct-fit component for threaded spring plunger applications requiring a 1/4-28 thread size and standard plunger projection in light-duty industrial and tooling fixtures.

Installation Notes

Installation is typically performed by maintenance technicians or tooling specialists using a hex wrench or spanner tool appropriate for the plunger body style. Thread the plunger into a pre-tapped 1/4-28 bore and tighten to seat the locking element against the bore wall before applying load. De-energize or lock out any associated equipment before servicing plungers in active fixtures or assemblies. Avoid overtightening, which can deform the locking element and reduce retention performance.