Electro Hardware THS1002M01F21 Brass Thumb Screw 4-40

Product Description

The ELECTRO HARDWARE THS1002M01F21 is a brass thumb screw with a 4-40 UNC thread and a knurled head, designed for tool-free fastening in light-duty mechanical and electrical assemblies. The knurled head provides reliable finger grip for frequent adjustments or removals without a screwdriver. At 5/8 inch overall length with a shouldered shank, this fastener suits applications where alignment or a positive stop is required. The head measures 3/8 inch in diameter and 3/16 inch in height. Base material is brass with a zinc finish, making it suitable for environments where mild corrosion resistance and low magnetic signature matter to the installer or technician.

This thumb screw is a standard inch-series fastener used in panel assemblies, electrical enclosures, instrument housings, and control boxes where hand-tightened access points are needed. The 4-40 thread size is common in small electronic and HVAC control panel hardware, terminal covers, and access plates. The with-shoulder design provides a consistent bearing surface and is useful where the fastener must register against a mating component. Tradespeople, panel builders, and assembly technicians working on control enclosures and instrumentation regularly specify this type of fastener for removable covers and field-serviceable access points.

Key Features

• 4-40 UNC thread for compatibility with standard small-pitch tapped holes in panels and enclosures
• Knurled head allows tool-free installation and removal by hand
• With-shoulder design provides a positive bearing surface and alignment reference
• Brass construction with zinc finish for mild corrosion resistance and low magnetic interference
• 3/8 inch head diameter and 3/16 inch head height for low-profile, flush-friendly installations
• Meets multiple material and finish standards including ASTM B633

Compatibility

Designed as a standard 4-40 UNC inch-series thumb screw suitable for tapped holes in electrical enclosures, control panels, and instrument assemblies requiring a hand-tightened shouldered fastener.

Installation Notes

This fastener is installed by hand into a pre-tapped 4-40 UNC hole. De-energize any electrical panel or enclosure before servicing access covers secured by these screws, following applicable NEC guidelines. Do not use power tools to drive or remove this thumb screw, as the knurled head is designed for finger torque only and the brass material can be damaged by excessive force. Verify that the mating tapped hole thread standard matches 4-40 UNC before installation.