Vlier NM56 Threaded Spring Plunger 5/16-18 Steel

Product Description

The VLIER NM56 is a stubby threaded spring plunger designed for indexing, positioning, and light-duty detent applications in mechanical assemblies. It features a 5/16-18 thread with a 0.562-inch thread length and a maximum plunger diameter of 0.135 inches. The plunger delivers 3.75 pounds of initial end force and 15.5 pounds of final end force, making it suitable for applications that require a firm, repeatable snap engagement. The steel body provides structural durability, while the Delrin nose reduces friction and wear against mating surfaces. This plunger is typically installed by machinists, mechanical assemblers, or maintenance technicians working on fixtures, tooling, or precision equipment.

The NM56 is used in applications where a compact, low-profile spring plunger is needed and thread depth is limited. The stubby body length of 0.562 inches suits tight clearance scenarios in jigs, fixtures, machine frames, and similar assemblies. It installs directly into a threaded hole and requires no additional hardware. The Delrin nose is appropriate for use against metal, plastic, or coated surfaces where marring must be minimized.

Key Features

• Stubby plunger length type at 0.562 inches for tight clearance installations
• 5/16-18 thread for broad compatibility with standard tapped holes
• 3.75-pound initial end force and 15.5-pound final end force for firm detent engagement
• Steel body for mechanical strength and durability
• Delrin nose reduces friction and protects mating surfaces from wear or marring
• No locking element, allowing the plunger to be adjusted or removed without special tools

Compatibility

Designed as an OEM-style replacement or direct-install threaded spring plunger for standard 5/16-18 tapped holes in mechanical fixtures, tooling, and assembly equipment.

Installation Notes

Installation is performed by threading the NM56 into a properly tapped 5/16-18 hole using a hex key or spanner wrench as appropriate for the drive style. Ensure the mating assembly is depressurized or de-energized before servicing any fixture or machine component. Do not overtighten, as excessive torque can damage the plunger body or distort the spring mechanism. Verify plunger projection and force requirements match the detent or indexing load of the application before final installation.