Electro Hardware S789-M10-F21-H Round Circuit Board Spacer

Product Description

The ELECTRO HARDWARE S789-M10-F21-H is a round, female unthreaded circuit board spacer machined from Grade 2 steel with a zinc-plated finish. It is designed to maintain precise standoff distance between a printed circuit board and a mounting surface, preventing electrical contact and mechanical stress. The spacer measures 0.1875 inches in overall length, 0.171 inches inside diameter, and 0.3125 inches outside diameter. It accepts a number 8 screw. The zinc plating meets ASTM B633 and QQ-S-633 Type 1 standards, providing corrosion resistance in light-duty indoor environments. Electronics technicians, HVAC controls installers, and electrical panel assemblers use this type of hardware when mounting control boards inside equipment enclosures.

This spacer is suited for use in residential and light commercial electronic assemblies where a number 8 fastener is used to secure a circuit board. Typical applications include HVAC control board mounting, electrical enclosure subassemblies, and industrial electronics where consistent board standoff and electrical isolation from the chassis are required. Its compact 0.1875-inch length makes it appropriate for low-profile board installations with tight clearance requirements.

Key Features

• Female unthreaded round body accepts a number 8 screw for straightforward board mounting
• Overall length of 0.1875 inches with a tight length tolerance of -0.005 to 0.005 inches for consistent standoff height
• Inside diameter of 0.171 inches with a tolerance of 0.000 to 0.010 inches for reliable fastener fit
• Outside diameter of 0.3125 inches provides a stable bearing surface on the board or chassis
• Zinc-plated Grade 2 steel construction meets ASTM B633 and QQ-S-633 Type 1 standards
• Inch measurement system; sold individually with no minimum order quantity above one piece

Compatibility

Designed as a standard inch-series circuit board spacer for any assembly requiring a female unthreaded round standoff with a number 8 screw clearance, 0.1875-inch standoff height, and a 0.3125-inch outside diameter bearing surface.

Installation Notes

Installation is typically performed by electronics technicians or HVAC controls specialists during board mounting or replacement. Power down and de-energize the equipment fully before handling any circuit board hardware. The female unthreaded design requires a mating number 8 fastener to be inserted through the board and spacer into the chassis or standoff below. Verify that the chosen fastener length accounts for the full 0.1875-inch spacer height plus the board thickness and any chassis wall dimension.