Electro Hardware P509M12F21-440 Hex Standoff 4-40

Product Description

The ELECTRO HARDWARE P509M12F21-440 is a female hex circuit board standoff designed to create controlled spacing between printed circuit boards and mounting surfaces. Machined from Grade 2 steel with a zinc-plated clear chromate finish, this standoff meets ASTM B633 Type 1 and QQ-S-633 standards for corrosion resistance and finish quality. The hex body shape allows easy installation and removal with standard hex drivers or wrenches. With a 4-40 female thread, 3/16 inch overall length, and 1/4 inch width across flats, this standoff suits compact PCB assemblies where precise, low-profile board separation is required.

This standoff is used in residential and commercial electronics assembly, control panel fabrication, and HVAC or electrical equipment where circuit boards must be mounted securely off a chassis or secondary board. It is appropriate for applications requiring inch-measurement fasteners with a 4-40 thread pattern. Electricians, control panel builders, and electronics technicians typically install these as part of board mounting hardware sets during equipment assembly or field service.

Key Features

• Female 4-40 thread accepts standard 4-40 male fasteners for secure board-to-board or board-to-chassis mounting
• Hex body shape allows tool-assisted installation and removal without slipping
• Zinc-plated clear chromate finish meets ASTM B633 Type 1 and QQ-S-633 for corrosion protection
• Grade 2 steel construction provides reliable mechanical strength in light-duty mounting applications
• Compact 3/16 inch overall length suits tight PCB stack spacing
• Inch measurement system with length tolerance of -0.005 to 0.005 inches ensures consistent fitment

Compatibility

Designed as an OEM-style replacement or new-installation standoff for circuit board assemblies using 4-40 inch-series thread fasteners in control panels, HVAC equipment boards, and general electronics enclosures.

Installation Notes

Installation is typically performed by licensed electricians or electronics technicians during board assembly or field service. Power down all circuits and discharge any capacitors before working on or near circuit boards. A hex driver or appropriately sized wrench sized for 1/4 inch across flats is recommended for proper torque without damaging the standoff or board. Follow applicable NEC guidelines when installing control board hardware inside electrical enclosures.