Vlier S57 Threaded Spring Plunger 5/16-18 Steel

Product Description

The VLIER S57 is a standard threaded spring plunger designed to provide controlled, repeatable positioning force in precision assemblies, fixtures, and tooling applications. The S57 features a 5/16-18 thread with a 1 inch thread length and a steel body. The plunger nose delivers an initial end force of 1.5 lb and a final end force of 4.5 lb, making it suitable for light-duty indexing, detenting, and positioning functions. The plunger diameter ranges from 0.133 inches minimum to 0.135 inches maximum, with a 3/16 inch projection. Both the body and nose are steel construction for durability in industrial environments. Machinists, tool and die makers, and mechanical assembly technicians are the primary installers of this component.

The S57 threaded spring plunger is used in machine tool fixtures, jigs, workholding devices, and mechanical assemblies where a spring-loaded ball or pin is needed to locate, index, or retain a moving component. It threads directly into a tapped hole and requires no additional hardware. Applications include production fixtures in manufacturing settings, positioning stops on sliding components, and light detent functions in mechanical devices. The standard plunger length type makes this a straightforward drop-in for new builds or replacement in existing assemblies using 5/16-18 threaded bores.

Key Features

• 5/16-18 thread size with 1 inch thread length for secure installation in standard tapped bores
• 1.5 lb initial end force and 4.5 lb final end force for repeatable light-duty indexing and detenting
• Plunger projection of 3/16 inch provides reliable engagement with mating surfaces
• Steel body and steel nose material for strength and wear resistance in industrial use
• No locking element - allows removal and repositioning without thread-locking compounds
• Standard plunger length type for straightforward replacement in existing assemblies

Compatibility

Designed as an OEM-style replacement or new-build component for any assembly requiring a 5/16-18 threaded spring plunger with standard 1 inch body length and steel construction.

Installation Notes

Installation is performed by machinists or mechanical assembly technicians using a hex wrench or screwdriver slot appropriate to the plunger head style. The receiving bore must be tapped to 5/16-18 and clean before installation. Do not overtighten, as this can compress the internal spring beyond its working range and reduce plunger performance. Inspect the bore for chips or debris that could interfere with plunger travel before seating the component.