Electro Hardware S513-M10-F21-E Circuit Board Spacer No. 4

Product Description

The ELECTRO HARDWARE S513-M10-F21-E is a round, female unthreaded circuit board spacer machined from Grade 2 steel with a zinc-plated finish. It is designed to create a fixed standoff distance between a printed circuit board and a mounting surface. The spacer has an overall length of 0.25 inches, an outside diameter of 0.25 inches, and an inside diameter of 0.116 inches, sized for a No. 4 screw. The zinc plating meets ASTM B633 and QQ-S-633 Type 1 standards, providing corrosion resistance in typical indoor electronic and control board assemblies. Electronics technicians, HVAC controls installers, and electrical panel assemblers commonly work with this hardware type.

This spacer is used in printed circuit board mounting applications where a No. 4 fastener is required. The female unthreaded bore accepts a screw passed through from the board side, allowing the spacer to function as a standoff or isolation collar. Typical applications include control board assemblies in HVAC equipment, electrical enclosures, and light commercial electronics. The round body and consistent dimensional tolerances make it suitable for high-density board layouts where precise spacing is critical.

Key Features

• Female unthreaded design accepts No. 4 screws for straightforward board mounting
• Grade 2 steel construction provides reliable mechanical strength for standoff applications
• Zinc-plated finish per ASTM B633 and QQ-S-633 Type 1 for corrosion resistance
• Overall length of 0.25 inches with tight length tolerance of -0.005 to 0.005 inches for consistent board clearance
• Inside diameter tolerance of 0.000 to 0.010 inches ensures proper fastener fit
• Round body profile compatible with standard PCB mounting hole patterns

Compatibility

Designed for use with No. 4 screw fasteners in printed circuit board standoff and spacer applications across HVAC control boards, electrical enclosures, and general electronics assemblies.

Installation Notes

Installation is performed by electronics technicians or electricians during control board assembly or replacement. Power down and de-energize all circuits before working on any board mounting hardware. Use appropriately sized No. 4 fasteners to avoid stripping the unthreaded bore or damaging the board. Follow applicable NEC guidelines and equipment manufacturer instructions when replacing or servicing control board assemblies.