Electro Hardware THS1004M04F16 Aluminum Thumb Screw 4-40

Product Description

The ELECTRO HARDWARE THS1004M04F16 is an aluminum thumb screw with a knurled head and integral shoulder, designed for tool-free fastening in panel assemblies, enclosures, and instrumentation hardware. The 4-40 UNC thread is a standard fine-pitch size widely used in electrical panels, control boxes, and light-duty mechanical assemblies. The knurled head provides reliable finger grip for hand-tightening without a driver. Overall length is 0.75 inches, with an uncoated aluminum body that keeps weight minimal. The shoulder diameter is 0.312 inches and shoulder length is 0.125 inches, making this screw suitable for applications where a locating or bearing surface is needed alongside the threaded section.

This thumb screw is used in residential and commercial electrical enclosures, HVAC control panels, low-voltage equipment covers, and instrumentation cabinets where frequent access is required. The 4-40 UNC thread size is common in light sheet-metal and extruded aluminum assemblies. Electricians, HVAC technicians, and panel fabricators install this fastener wherever hand-removal of covers or sub-panels is a routine service requirement. It ships and is sold individually, with a minimum order quantity of 10 pieces per order.

Key Features

• 4-40 UNC thread for compatibility with standard light-duty panel and enclosure hardware
• Knurled head allows tool-free hand tightening and removal
• Integral shoulder at 0.312 inches diameter and 0.125 inches length provides a positive locating surface
• Uncoated aluminum construction keeps weight low and resists galvanic issues in aluminum enclosures
• Meets QQ-A-225A Comp 2 and T-3 material standards
• Head diameter of 0.375 inches and head height of 0.1875 inches provide a low-profile grip surface

Compatibility

Designed as an OEM-style replacement or stock fastener for electrical enclosures, control panels, and instrumentation assemblies that use 4-40 UNC threaded hardware with a knurled thumb screw interface.

Installation Notes

Install and remove by hand only. Do not use a driver or wrench on the knurled head, as aluminum threads and the head profile are not rated for torqued installation. Before servicing any electrical enclosure or control panel, de-energize the equipment and verify lockout-tagout procedures per applicable NEC requirements. Confirm thread engagement depth in the mating component is sufficient for the fastener application before finalizing the installation.