Vlier SLR312P Locking Knob Plunger 5/16-18 Thread

Product Description

The VLIER SLR312P is a spring plunger with a locking knob handle, designed to locate, hold, or index mechanical components in industrial and manufacturing assemblies. The 5/16-18 threaded body installs into a tapped hole and provides a retractable plunger that locks in the retracted position using a countersunk knob, allowing hands-free positioning during assembly operations. Thread length is 0.53 inches and the body measures 1.07 inches long. Initial end force is 1 pound, rising to a final end force of 6 pounds, giving the installer a clear tactile range for indexing and retention applications. Maximum plunger diameter is 0.154 inches. This part is installed by machinists, toolmakers, and mechanical assembly technicians.

The SLR312P is suited for jigs, fixtures, machine tool components, and production assembly tooling where a positive locking plunger is needed to hold a position without continuous operator force. The countersunk knob style keeps the head profile low, reducing interference with adjacent components or sliding surfaces. The locking feature disengages the plunger spring load so operators can retract and hold the plunger out of the way during loading or unloading cycles. Typical installations are found in light industrial machinery, fixture plates, and positioning systems requiring repeatable engagement.

Key Features

• Locking plunger retracts and holds in the retracted position via countersunk knob
• 5/16-18 thread for installation in standard tapped holes
• Initial end force of 1 pound to final end force of 6 pounds for positive indexing feedback
• Maximum plunger diameter of 0.154 inches with a projection of 0.187 inches
• Head diameter of 0.875 inches with 1/8-inch hex drive for installation and removal
• Compact 1.07-inch body length for installations with limited depth clearance

Compatibility

Designed as an OEM-style replacement or direct installation component for fixtures, jigs, and mechanical assemblies requiring a 5/16-18 threaded locking spring plunger with a countersunk knob handle.

Installation Notes

Install using a 1/8-inch hex key into a properly tapped 5/16-18 blind or through hole. Ensure the mating bore for the plunger tip is aligned and deburred before threading in the body. Do not overtighten the body, as this can distort the thread or affect plunger travel. Confirm plunger locking and release function freely before placing the assembly into service.