Vlier S55AN Threaded Spring Plunger 1/4-28 Steel Locking

Product Description

The VLIER S55AN is a standard threaded spring plunger designed for indexing, positioning, and light-duty holding applications in industrial assemblies and fixtures. The plunger body and nose are both constructed from steel, providing durability under repeated cycling. It features a 1/4-28 thread with a 1 inch thread length, a plunger projection of 3/16 inches, and a plunger diameter range of 0.117 to 0.118 inches. A built-in locking element secures the plunger in place once installed, preventing back-out from vibration or torque. This component is installed by machinists, tool-and-die technicians, and mechanical assembly professionals working with precision fixtures, jigs, and machine tooling.

The S55AN is suited for use in threaded bores on fixture plates, machine bases, and assembly tooling where consistent spring-loaded positioning force is required. The 1/4-28 fine thread provides positive engagement in both ferrous and non-ferrous threaded holes. With an initial end force of 1 pound and a final end force of 4 pounds, it is appropriate for light positioning and detent applications that require a predictable, repeatable actuation force across production runs.

Key Features

• 1/4-28 fine thread with 1 inch thread length for secure installation in standard threaded bores
• Steel body and steel nose for wear resistance and long service life
• Locking element prevents back-out under vibration or torque
• Plunger projection of 3/16 inches suits standard indexing and detent applications
• Initial end force of 1 pound and final end force of 4 pounds provide consistent, predictable actuation
• Standard plunger length type allows straightforward replacement in existing fixturing

Compatibility

Designed as a direct-fit replacement or new-installation threaded spring plunger for fixtures, jigs, and machine tooling that accept a 1/4-28 threaded spring plunger with a standard plunger length configuration.

Installation Notes

Installation is typically performed by machinists or mechanical assembly technicians using a hex key or spanner wrench appropriate for the plunger body style. Ensure the receiving threaded bore is clean and within tolerance before installation. The locking element is engaged during installation and should not be modified or removed. De-energize or lock out any powered equipment before servicing fixtures or tooling that contain spring plungers.