Vlier SCH330 Thumb Screw 1/4-20 Knurled Head Steel

Product Description

The VLIER SCH330 is a steel thumb screw designed for hand-tightening applications where no tools are required. It features a knurled head for a secure grip and a swivel pad tip that adjusts to uneven surfaces during clamping or positioning tasks. The screw has a 1/4-20 UNC thread and measures 2.375 inches in overall length with a 1 inch head diameter and a 3/8 inch head height. A black oxide finish provides mild corrosion resistance. This fastener is commonly installed by machinists, toolmakers, and mechanical assembly technicians in fixture, jig, and workholding setups.

This thumb screw suits light industrial and mechanical assembly applications where frequent manual adjustment is needed without tools. The swivel pad tip, with a 7.5-degree swivel angle, compensates for slight surface irregularities and distributes clamping load more evenly. It is a practical choice for use in drill fixtures, inspection setups, and machine tool accessories where quick-release or repeated repositioning is routine.

Key Features

• Knurled head design enables hand tightening without tools
• Swivel pad tip with 7.5-degree swivel angle accommodates uneven contact surfaces
• 1/4-20 UNC thread standard for broad compatibility with inch-system hardware
• Black oxide finish provides mild corrosion and wear resistance
• Without-shoulder configuration for straightforward through-hole installation
• Manufactured to ISO 9001 quality standards

Compatibility

Designed as a standard 1/4-20 UNC inch-system thumb screw suitable for use in tooling fixtures, jigs, and mechanical assemblies that accept this thread size and head style.

Installation Notes

This thumb screw is installed by hand or with light tool assistance into a tapped 1/4-20 UNC hole. Ensure the mating thread is clean and free of debris before installation. Do not overtighten, as the knurled head and swivel tip are intended for hand-load applications only. Verify that the swivel pad has full contact with the work surface before applying clamping force.