Electro Hardware MMF1321M09F16M3 Hex Standoff M3x0.5

Product Description

The ELECTRO HARDWARE MMF1321M09F16M3 is a male-female hex circuit board standoff designed to space and secure printed circuit boards within electronic enclosures and control assemblies. Machined from 303 stainless steel with a bright uncoated finish, it meets the QQ-S-763 federal specification for corrosion resistance and dimensional consistency. The standoff features an M3 x 0.5 thread on both the male and female ends, an overall length of 19.76 mm (approximately 0.778 inches), a hex body width across flats of 4.50 mm, and a body length of 15.00 mm. It is installed using standard hex drivers and is suited for environments where stainless steel is required to resist moisture or mild chemicals.

This standoff is used wherever a PCB must be mounted at a fixed height above a chassis surface or stacked above another board in a layered assembly. Common applications include HVAC control boards, electrical panel sub-assemblies, industrial enclosures, and OEM equipment builds. The male end threads into a tapped hole or a previously installed female standoff, while the female end accepts a machine screw to secure the board above. This configuration allows for tiered PCB stacking or single-board mounting with a fixed standoff height. Installation is performed by technicians and assemblers working on electronic control systems.

Key Features

• M3 x 0.5 male and female threads on opposite ends for stacked or single-board mounting
• 303 stainless steel construction meeting QQ-S-763 federal specification
• Hex body profile - 4.50 mm across flats - for positive wrench engagement during installation
• Overall length of 19.76 mm with a length tolerance of -0.150 to +0.150 mm
• Bright uncoated finish - no added coating that could affect dimensional tolerances in tight assemblies
• Metric system of measurement throughout all dimensions

Compatibility

Designed for use in M3-threaded PCB mounting applications requiring a male-female hex standoff configuration. Suitable for circuit boards with standard M3 clearance or tapped holes in any assembly where a 4.50 mm hex body profile fits the available footprint.

Installation Notes

Install and remove using a 4.50 mm hex wrench or appropriately sized nut driver. De-energize all circuits and discharge any stored energy in the control assembly before handling PCBs or standoffs. Do not overtighten - 303 stainless steel fasteners can gall if driven with excessive torque, particularly when threading into a stainless female standoff or tapped stainless hole. Inspect threads on both the male pin and female bore before installation to confirm they are clean and undamaged.