Vlier PRTL375 Locking Knob Handle Plunger 3/8-16

Product Description

The VLIER PRTL375 is a locking knob handle plunger designed for positioning, indexing, and retention applications in industrial and mechanical assemblies. It features a 3/8-16 thread size and a maximum plunger diameter of 0.25 inches, with a Delrin knob handle that allows the operator to retract and lock the plunger in the retracted position for hands-free access. Initial end force is 0.25 pounds and final end force is 2 pounds, providing a controlled spring-loaded engagement range suited to light-duty locating and holding tasks. The body length is 0.94 inches with a thread length of 0.75 inches under the head and shoulder.

This plunger is used in jigs, fixtures, machine guarding, tooling plates, and similar assemblies where a retractable, lockable locating pin is required. The locking knob style allows technicians and assemblers to hold the plunger in the retracted position during workpiece loading or repositioning, then release it for positive engagement. It is installed by machinists, tool and die technicians, and maintenance mechanics working with production fixtures or custom fabrication assemblies. The black finish provides basic corrosion resistance for typical shop environments.

Key Features

• Locking plunger type holds retracted position for hands-free workpiece handling
• Delrin knob handle for comfortable manual operation without tooling
• 3/8-16 thread size for straightforward installation into standard tapped holes
• End force range of 0.25 pounds initial to 2 pounds final for light-duty indexing
• Steel construction with black finish for durability in shop environments
• Compact body length of 0.94 inches suits space-constrained assemblies

Compatibility

Designed as a direct-fit locking knob handle plunger for assemblies using a 3/8-16 threaded mounting hole, typical of industrial jigs, fixtures, and tooling plate applications.

Installation Notes

Installation is performed by threading the PRTL375 into a pre-tapped 3/8-16 hole using the hex feature for wrench engagement. Ensure the mating thread bore is clean and free of debris before installation. De-energize or lock out any powered equipment before servicing assemblies that incorporate this plunger. Do not exceed the rated end force range by modifying the spring or plunger mechanism.