Electro Hardware S553-M10-F21-E Circuit Board Spacer

Product Description

The ELECTRO HARDWARE S553-M10-F21-E is a round, female unthreaded circuit board spacer designed to provide consistent standoff clearance between a PCB and a mounting surface. Manufactured from Grade 2 steel with a zinc-plated finish per ASTM B633 and QQ-S-633 Type 1, this spacer delivers corrosion resistance suitable for electronics enclosures, control panels, and industrial assemblies. It measures 0.875 inches in overall length with an inside diameter of 0.116 inches and an outside diameter of 0.25 inches, sized for a No. 4 screw. HVAC controls technicians, electricians, and electronics assembly professionals install this hardware during control board mounting and enclosure fabrication.

This spacer is used in residential and light commercial control panel assemblies, circuit board mounting applications, and electronics enclosures where a consistent, non-threaded standoff is required. It accepts a No. 4 fastener and provides a clean female unthreaded bore for pass-through or stacking configurations. The zinc-plated steel construction makes it suitable for indoor electrical enclosures and HVAC control board installations where mild corrosion resistance is needed.

Key Features

• Female unthreaded bore accepts No. 4 screw for flexible mounting configurations
• Overall length of 0.875 inches provides reliable PCB standoff clearance
• Inside diameter of 0.116 inches with a tolerance of 0.000 to 0.010 inches
• Outside diameter of 0.25 inches in a round body profile
• Grade 2 steel construction with zinc-plated finish per ASTM B633 and QQ-S-633 Type 1
• Length tolerance held to -0.005 to 0.005 inches for consistent stack height

Compatibility

Designed as an OEM-style replacement or new-installation spacer for circuit board mounting applications requiring a No. 4 screw, female unthreaded round standoff in inch measurement.

Installation Notes

Installation is performed by licensed electricians, electronics technicians, or HVAC controls professionals. De-energize and lock out the panel or control board assembly before handling any PCB hardware. Use the appropriately sized No. 4 fastener and avoid over-torquing, which can crack the board or deform the spacer. Follow applicable NEC guidelines for control panel assembly and wiring clearances.