Electro Hardware S309M10F21E Circuit Board Spacer Steel

Product Description

The ELECTRO HARDWARE S309M10F21E is a round, female unthreaded circuit board spacer designed to maintain precise standoff distances between a PCB and a mounting surface or between stacked boards. Built from Grade 2 steel with a zinc-plated finish meeting ASTM B633 and QQ-S-633 Type 1 standards, this spacer delivers corrosion resistance and dimensional consistency in tight tolerances. It measures 0.5 inches in overall length, with an inside diameter of 0.116 inches and an outside diameter of 0.1875 inches. It is sized for a No. 4 screw. Electronics assembly technicians, industrial maintenance personnel, and control board installers use this type of spacer during PCB mounting and enclosure builds.

This spacer is suited for use in residential and light commercial electronic control assemblies, HVAC circuit board installations, relay panels, and general electrical enclosure builds where a No. 4 fastener is specified. The zinc-plated finish makes it appropriate for indoor and semi-protected environments where mild corrosion resistance is required. Its compact outside diameter of 0.1875 inches allows placement in densely populated board layouts without interfering with adjacent components.

Key Features

• Female unthreaded design sized for No. 4 screws
• Grade 2 steel construction with zinc-plated finish per ASTM B633 and QQ-S-633 Type 1
• Overall length of 0.5 inches with a tight length tolerance of -0.005 to 0.005 inches
• Inside diameter of 0.116 inches with a tolerance of 0.000 to 0.010 inches
• Outside diameter of 0.1875 inches for use in compact board layouts
• Round body shape for consistent standoff and stable seating on flat surfaces

Compatibility

Designed as a standard-fitment round circuit board spacer for PCB mounting applications using No. 4 screw hardware in electrical and electronic control assemblies.

Installation Notes

Installation is typically performed by electronics technicians or licensed electricians during control board assembly or replacement. De-energize all circuits and discharge any stored capacitance before handling circuit boards or installing spacers. Use appropriately sized No. 4 fasteners and avoid over-torquing, which can crack the board substrate or deform the spacer. Verify spacer placement meets the board manufacturer's standoff requirements before final assembly.