Electro Hardware MMF1339M03F21M3 Hex Standoff M3x0.5

Product Description

The ELECTRO HARDWARE MMF1339M03F21M3 is a male-female hex circuit board standoff designed to create fixed spacing between PCBs, enclosure panels, and mounting surfaces in electronic assemblies. Machined from brass with a zinc-plated finish meeting ASTM B633 Type 1 and QQ-B-626 Comp 22 standards, this standoff provides corrosion resistance and reliable conductivity in tight board-stack configurations. The M3 x 0.5 thread on both the male pin and female bore ensures clean engagement with standard metric hardware. The hex body measures 4.5 mm across flats, allowing installation and removal with a standard hex wrench or nut driver. Overall length is 28.76 mm with a body length of 24.00 mm.

This standoff is suited for residential and commercial electronics, control board assemblies, HVAC control panels, and industrial enclosures where PCB-to-PCB or PCB-to-chassis separation is required. Electricians, electronics technicians, and panel builders use this type of fastener when assembling or servicing multi-board stacks or securing circuit boards to back panels. The metric M3 sizing is common in OEM control board assemblies and field repair applications across a range of trade equipment.

Key Features

• Brass construction with zinc-plated finish for corrosion resistance and electrical conductivity
• M3 x 0.5 thread on both male and female ends for standard metric compatibility
• Hex body at 4.5 mm across flats allows wrench or nut driver installation
• Overall length of 28.76 mm with a 24.00 mm body length for defined board spacing
• Meets ASTM B633 Type 1 and QQ-B-626 Comp 22 finish standards
• Length tolerance of -0.150 to 0.150 mm for consistent stack height

Compatibility

Designed as an OEM-style replacement or new-installation standoff for metric M3 x 0.5 circuit board mounting applications in electronic assemblies, control panels, and enclosures.

Installation Notes

Installation is typically performed by an electronics technician or electrician during board assembly or service. De-energize and discharge all circuits before handling circuit boards or standoffs in live panels. Use a properly sized hex wrench or nut driver matched to the 4.5 mm across-flats hex body to avoid rounding the standoff. Do not overtighten, as brass fasteners in PCB applications can crack board mounting holes if excessive torque is applied.