Electro Hardware S1391-M10-F21-I Circuit Board Spacer

Product Description

The ELECTRO HARDWARE S1391-M10-F21-I is a round, female unthreaded circuit board spacer designed to create a fixed standoff gap between a printed circuit board and a mounting surface. Machined from Grade 2 steel with a zinc-plated finish per ASTM B633 and QQ-S-633 Type 1, this spacer provides corrosion resistance and reliable dimensional stability under service conditions. It accepts a Number 10 screw, measures 1 inch overall length, 0.194 inches inside diameter, and 0.5 inches outside diameter. Licensed electricians and electronics technicians use this fastener when mounting control boards, relay panels, or PCB assemblies in HVAC equipment, electrical enclosures, and industrial control panels.

This spacer is suited for residential and commercial applications where a Number 10 screw is the specified fastener and a 1-inch standoff height is required. Common install scenarios include securing circuit boards inside furnace control compartments, air handler electrical panels, and similar enclosures where board clearance and vibration isolation are required. The inch-measurement system and standard sizing make it a direct fit in typical domestic OEM and aftermarket board mounting applications.

Key Features

• Female unthreaded round body accepts Number 10 screws for secure board mounting
• 1 inch overall length with a tight length tolerance of -0.005 to 0.005 inches
• 0.194 inches inside diameter with inside diameter tolerance of 0.000 to 0.010 inches
• 0.5 inches outside diameter for compact footprint on dense PCB layouts
• Grade 2 steel construction with zinc-plated finish meets ASTM B633 and QQ-S-633 Type 1
• Inch measurement system; compatible with standard domestic fastener tooling

Compatibility

Designed as an OEM-style replacement or new-installation spacer for circuit board mounting applications that specify a Number 10 screw and a 1-inch standoff height in inch-dimensioned assemblies.

Installation Notes

Installation is performed by licensed electricians or qualified electronics technicians. Always de-energize and lockout the equipment before removing or installing circuit board hardware. Use a properly sized Number 10 screw and avoid over-tightening, which can crack the PCB substrate or distort the spacer body. Follow applicable NEC requirements for work inside electrical enclosures.