Electro Hardware S309M10F21C Circuit Board Spacer Steel

Product Description

The ELECTRO HARDWARE S309M10F21C is a round, female unthreaded circuit board spacer designed to maintain precise standoff distances between PCBs and mounting surfaces in electronic assemblies. Manufactured from Grade 2 steel with a zinc-plated finish meeting ASTM B633 and QQ-S-633 Type 1 standards, this spacer measures 0.5 inches overall length with a 0.1875-inch outside diameter and a 0.089-inch inside diameter. It is sized for a No. 2 screw and provides consistent board-to-board or board-to-chassis separation in control panels, HVAC control boards, and other low-voltage electronic enclosures. The zinc plating offers corrosion resistance suited to indoor electrical environments.

This spacer is used wherever a No. 2 screw fastener is required to secure a circuit board at a fixed standoff height. Common applications include residential and light commercial HVAC control boards, electrical panel assemblies, and industrial electronic enclosures where consistent PCB spacing is critical for heat dissipation, vibration isolation, and prevention of short circuits against metal chassis surfaces. It installs in both OEM manufacturing and field service replacement contexts.

Key Features

• Female unthreaded design accepts a No. 2 screw from each end for secure two-point board mounting
• 0.5-inch overall length provides a fixed standoff between the circuit board and mounting surface
• Grade 2 steel construction meets ASTM B633 and QQ-S-633 Type 1 fastener standards
• Zinc-plated finish provides corrosion resistance for indoor electrical enclosure use
• Inside diameter tolerance of 0.000 to 0.010 inches and length tolerance of -0.005 to 0.005 inches for consistent fitment
• Round body shape for standard PCB mounting hole patterns

Compatibility

Designed as an OEM-style replacement or new-installation spacer for circuit board assemblies requiring a No. 2 screw, 0.5-inch standoff height, and a 3/16-inch outside diameter round spacer in steel construction.

Installation Notes

Installation is performed by electricians or electronics technicians during control board service or panel assembly. Always de-energize and lock out the equipment before removing or installing circuit board hardware. Use a properly sized No. 2 screw driver to avoid stripping the mating fastener. Follow applicable NEC guidelines for control panel assembly and ensure the spacer does not create unintended contact with adjacent conductors or grounded surfaces.