Gibraltar 34239SS Locking Knob Plunger 1/2-13 Stainless Steel

Product Description

The GIBRALTAR 34239SS is a locking knob-style plunger with a threaded stud body, designed for use in workholding, fixturing, and positioning applications across industrial and mechanical assemblies. The unit features a 1/2-13 thread size with a thread length of 0.875 inches and a stud thread size of 3/8-16. The plunger delivers an initial end force of 2.5 pounds and a final end force of 10 pounds, with a maximum plunger diameter of 0.31 inches and a plunger length of 1.937 inches. Constructed from stainless steel with a zinc-plated finish, this plunger is suited for environments where corrosion resistance and repeatable locking performance are required. Licensed tradespeople and machine maintenance technicians handle installation in production and mechanical service settings.

This plunger is applied in machine tool fixtures, jigs, and positioning assemblies where a knobless threaded stud configuration is needed for flush or low-profile mounting. The 1/4-inch plunger projection and 1-1/8-inch length under head allow for consistent engagement depth in typical fixture bores. The locking element engages to hold plunger position under load, making this part appropriate for vibration-prone or high-cycle applications in manufacturing and maintenance environments.

Key Features

• Locking plunger design with integral locking element to maintain set position under load
• 1/2-13 main thread with 3/8-16 stud thread for dual-thread mounting configurations
• Initial end force of 2.5 pounds, final end force of 10 pounds for controlled engagement
• Stainless steel construction with zinc-plated finish for corrosion resistance
• Knobless threaded stud style allows low-profile installation in tight assemblies
• Plunger diameter tolerance of plus 0.001 inches for precise bore fitment

Compatibility

Designed as a direct-replacement or new-installation locking plunger for industrial fixtures, jigs, and mechanical positioning assemblies requiring a 1/2-13 threaded body with a 3/8-16 stud.

Installation Notes

Installation is performed by qualified machine maintenance technicians or millwrights using standard thread engagement tools. Thread the body into the receiving bore to the specified length under head of 1.125 inches before securing. De-energize or lock out any associated machinery before servicing plunger assemblies per applicable OSHA lockout/tagout procedures. Do not exceed the rated final end force of 10 pounds to avoid damage to the locking element.