Value Collection 0408MST 4-40 X 1/2 in Truss Head Slotted Machine

Product Description

The VALUE COLLECTION 0408MST is a 4-40 x 1/2 inch truss head machine screw designed for secure mechanical fastening in light-duty assemblies. The slotted drive accepts a standard flat-blade screwdriver for straightforward installation. Constructed from steel with a zinc finish, this screw resists corrosion in typical indoor environments. The low-profile truss head distributes clamping load over a wider bearing surface compared to standard pan or round head styles, making it well-suited for thin or soft substrates. The thread is a unified coarse pitch 4-40, conforming to ASME B18.6.3 and SAE J82 standards. Length is measured under the head at 1/2 inch.

This screw is used across a wide range of light mechanical and electrical assembly applications including control panel fabrication, HVAC equipment enclosures, electrical junction boxes, and general sheet metal work. The 4-40 thread size is commonly found in instrument panels, small appliance housings, and terminal board mounting. It is installed by electricians, HVAC technicians, and mechanical assemblers wherever a compact, low-profile fastener is needed to secure thin components without a washer.

Key Features

• Truss head profile provides a wider bearing surface for use with thin or soft materials
• Slotted drive for installation with a standard flat-blade screwdriver
• 4-40 unified coarse thread for compatibility with standard 4-40 tapped holes and nuts
• Steel construction with zinc finish for corrosion resistance in indoor applications
• Meets ASME B18.6.3 and SAE J82 fastener standards
• No washer included; designed for direct-bearing installation

Compatibility

Designed as a standard 4-40 machine screw for use in any application requiring a 4-40 tapped hole or mating nut, without a washer, measured under the head at 1/2 inch.

Installation Notes

Install using a flat-blade screwdriver sized to the slot width to avoid cam-out and fastener damage. Do not overtighten steel screws into soft or thin substrates, as stripping the mating threads is possible with small diameter fasteners. Verify that the mating tapped hole or nut is also rated 4-40 before assembly. Follow applicable mechanical or electrical code requirements for panel and enclosure fastener specifications.