Electro Hardware THS1139M01F07 Brass Thumb Screw 1/4-20

Product Description

The ELECTRO HARDWARE THS1139M01F07 is a brass thumb screw designed for hand-tightened fastening applications where tools are not practical or permitted. Built to a 1/4-20 UNC thread standard, this screw features a knurled head for secure finger grip and a shoulder configuration that helps control insertion depth and alignment. The head measures 0.5 inches in diameter and 0.25 inches in height. The overall length is 1 inch. Finished in nickel over a brass body, it offers corrosion resistance suitable for light-duty panel, enclosure, and instrument assembly work. Electricians, HVAC technicians, and panel fabricators are the typical installers.

This thumb screw is suited for applications where frequent removal and reinstallation is required without tools — including electrical enclosure covers, instrumentation panels, HVAC access panels, and control cabinet assemblies. The knurled head provides reliable grip even in tight-clearance environments. The shoulder design helps locate the fastener consistently in matching threaded inserts or captured nuts. It is manufactured to inch-system dimensions and conforms to multiple material and finish standards, making it appropriate for both original equipment assembly and service replacement use.

Key Features

• 1/4-20 UNC thread for compatibility with standard inch-system hardware
• Knurled head profile for secure hand tightening without tools
• With-shoulder design aids alignment and depth control during installation
• Brass construction with nickel finish for corrosion resistance
• 0.5-inch head diameter and 0.25-inch head height for low-profile panel applications
• Meets ASTM B633 and multiple federal material and finish specifications

Compatibility

Designed as an OEM-style replacement or direct-fit fastener for applications using 1/4-20 UNC threaded inserts in panels, enclosures, and instrumentation assemblies requiring hand-removable hardware.

Installation Notes

Installation requires no tools under normal hand-tightening conditions. Ensure the mating threaded insert or nut is clean and free of debris before threading to avoid cross-threading the brass body. Do not use a wrench or driver on the knurled head, as brass is a soft material and the head may deform under excessive torque. Follow applicable electrical or mechanical enclosure codes when using this fastener on access panels that cover energized components.