Electro Hardware S561-M10-F21-E Circuit Board Spacer

Product Description

The ELECTRO HARDWARE S561-M10-F21-E is a round, female unthreaded circuit board spacer designed to create precise standoff clearance between a PCB and a mounting surface. Machined from Grade 2 steel with a zinc-plated finish, it measures 1 inch overall length with a 0.116 inch inside diameter and a 0.25 inch outside diameter. The female unthreaded body accepts a 4 screw and holds length tolerance within -0.005 to 0.005 inches for consistent stack height. Electronics technicians, field service engineers, and HVAC control board installers use this type of fastener hardware when securing logic boards, relay boards, or interface panels inside equipment enclosures.

This spacer suits residential and commercial electronics assembly, control panel builds, and PCB replacement work where a defined standoff height is required. Its compact 0.25 inch OD profile fits tightly spaced mounting patterns common in HVAC control boards, industrial relay panels, and light commercial equipment. The zinc-plated finish provides baseline corrosion resistance in indoor, non-condensing enclosure environments. It is sold individually, making it practical for single-board service calls or small-quantity repair jobs.

Key Features

• Female unthreaded round body sized for a 4 screw, providing clean PCB standoff without threading the spacer itself
• 1 inch overall length with tight length tolerance of -0.005 to 0.005 inches for consistent board clearance
• 0.116 inch inside diameter with tolerance of 0.000 to 0.010 inches for secure screw fit
• Grade 2 steel construction with zinc-plated finish meets ASTM B633 and QQ-S-633 Type 1 standards
• 0.25 inch outside diameter fits compact PCB mounting footprints
• Inch measurement system; single-piece packaging suits field repair and low-quantity assembly work

Compatibility

Designed as a standard inch-system round circuit board spacer for use with 4 screws in PCB mounting applications across electronics assembly, control panel fabrication, and field board replacement work.

Installation Notes

Installation is typically performed by electronics technicians or qualified HVAC or electrical service professionals. De-energize and lock out all power to the equipment before removing or replacing any control board hardware. Use appropriately sized 4 fasteners and avoid overtightening, which can crack PCB substrate or deform the spacer body. Verify standoff height requirements against the OEM board mounting specification before final assembly.