Vlier SCH334 Steel Thumb Screw 5/16-18 Knurled Head

Product Description

The VLIER SCH334 is a steel thumb screw with a knurled head and swivel pad tip, designed for tool-free adjustments and clamping applications in industrial and mechanical assemblies. It features a 5/16-18 UNC thread and measures 1.9375 inches in overall length. The knurled head provides grip for hand-tightening, while the swivel pad tip - with a 7.5-degree swivel angle and a tip diameter of 0.24 inches - accommodates slight angular misalignment and reduces marring on contact surfaces. A black oxide finish adds corrosion resistance and a consistent appearance. This fastener is installed by machinists, maintenance technicians, and assemblers working with fixtures, jigs, and precision equipment.

The SCH334 thumb screw is suited for use in fixture and tooling setups where repeated manual adjustment is required without the use of a wrench or driver. The swivel pad tip makes it appropriate for clamping against workpiece surfaces where surface protection is a consideration. Typical applications include machine tool fixtures, inspection equipment, and general mechanical assemblies requiring hand-adjustable retention. This is an inch-system fastener and is not interchangeable with metric thread standards.

Key Features

• 5/16-18 UNC thread for compatibility with standard inch-system tapped holes
• Knurled head at 1.125 inches diameter and 0.4375 inches height for secure hand grip
• Swivel pad tip with 7.5-degree swivel angle accommodates angular contact surfaces
• Tip diameter of 0.24 inches provides focused contact area
• Black oxide finish on steel construction for corrosion resistance
• No shoulder design for straightforward through-thread engagement

Compatibility

Designed as an OEM-style replacement or direct-fit fastener for industrial fixtures and mechanical assemblies using standard 5/16-18 UNC tapped holes requiring a hand-adjustable thumb screw with a swivel pad tip.

Installation Notes

Installation is performed by hand; no tools are required for standard tightening. Ensure the mating tapped hole is clean and free of debris before threading in the screw. Do not use a wrench or pliers on the knurled head, as this can deform the knurling and damage the head. Inspect the swivel pad tip for wear periodically in high-cycle clamping applications.