Gibraltar 31354LG Steel Thumb Screw 1/2-13 Knurled

Product Description

The GIBRALTAR 31354LG is a C12L14 steel thumb screw with a knurled head and swivel pad tip, designed for tool-free fastening and manual clamping applications across industrial and mechanical assembly work. The 1/2-13 UNC thread provides a coarse thread engagement suited for steel fixtures and jigs. A black oxide finish gives the fastener basic corrosion resistance in dry to mildly humid environments. At 3.5 inches overall length and 0.28 pounds, this thumb screw is a solid, hand-tightened fastener for positioning and workholding setups where frequent adjustment is expected.

This thumb screw is used in machine shop fixtures, tooling plates, fabrication jigs, and light industrial clamping assemblies. The 20-degree swivel pad tip allows the contact face to seat flush against workpiece surfaces that are not perfectly parallel, reducing the risk of marring or uneven clamping load. The knurled head diameter of 1.25 inches provides adequate grip surface for hand tightening without tools. Typical installers include machinists, tool-and-die technicians, maintenance mechanics, and fabricators working with steel or aluminum fixtures.

Key Features

• 1/2-13 UNC coarse thread for strong engagement in steel and aluminum fixtures
• Knurled head at 1.25 inches diameter for secure hand grip without tools
• Swivel pad tip with 20-degree swivel angle accommodates non-parallel clamping surfaces
• C12L14 steel construction with black oxide finish for corrosion resistance in dry environments
• 3/4-inch steel swivel tip diameter distributes clamping load across the workpiece
• Without-shoulder design for straightforward through-hole or tapped-hole installations

Compatibility

Designed as a standard UNC 1/2-13 thumb screw for use in tooling plates, machine fixtures, and fabrication jigs that require tool-free manual adjustment with a swivel pad clamping tip.

Installation Notes

Install into a tapped 1/2-13 UNC hole in the fixture body by hand. Verify thread engagement depth is sufficient before applying clamping load. The swivel pad tip should contact the workpiece surface squarely — inspect the swivel action prior to installation to confirm free movement. Do not use a wrench or driver on the knurled head, as this fastener is rated for hand torque only.