Vlier PH57N Threaded Spring Plunger 5/16-18 Steel Locking

Product Description

The VLIER PH57N is a threaded spring plunger designed for precise, repeatable positioning and indexing applications in industrial assemblies. It features a 5/16-18 thread size with a 1 inch thread length and a 0.135 inch maximum plunger diameter. The steel body and steel nose provide durability in demanding environments. A built-in locking element secures the plunger in its installed position, preventing loosening from vibration. Initial end force is 1.5 pounds, middle end force is 3 pounds, and final end force is 4.5 pounds, giving installers a defined force progression across the plunger travel. Suitable for use by machinists, toolmakers, and mechanical assembly technicians working in precision fixturing and jig applications.

The PH57N is used in tooling plates, jigs, fixtures, and mechanical assemblies where a spring-loaded ball or nose must engage a detent or indexing feature. The standard plunger length type makes it appropriate for common through-hole and tapped-hole installations. The locking element is especially useful in high-vibration environments where an unrestrained plunger would back out over time. Applications span general industrial machinery, fixture plates, and positioning assemblies across manufacturing and maintenance settings.

Key Features

• 5/16-18 thread with 1 inch thread length for standard tapped-hole installation
• Steel body and steel nose construction for wear and impact resistance
• Locking element prevents back-out under vibration
• Defined force curve: 1.5 pounds initial, 3 pounds middle, 4.5 pounds final end force
• Maximum plunger diameter of 0.135 inches with 3/16 inch projection
• 0.093 inch hex size for installation and torque adjustment

Compatibility

Designed as a standard threaded spring plunger for use in any tapped 5/16-18 hole in tooling plates, jigs, fixtures, and mechanical assemblies requiring spring-loaded positioning or indexing.

Installation Notes

Installation is performed by threading the plunger body into a tapped 5/16-18 hole using a hex key sized to the 0.093 inch hex. Ensure the receiving assembly is de-energized or immobilized before installation in any automated or powered fixture. The locking element should be engaged after the plunger is positioned at the correct depth. Do not overtighten, as this can compress the internal spring beyond its rated travel and reduce end force performance.